[PATCH v20 00/15]Timestamp synchronization of host - guest tracing session

[PATCH v20 00/15]Timestamp synchronization of host - guest tracing session

[Tzvetomir Stoyanov (VMware)]

Basic infrastructure for host - guest timestamp synchronization and a
POC implementation of PTP-like algorithm. 

[
 v20 changes:
  - Rebased on top of latest master.
  - Removed the VCPUS_MAX hardcoded limit, reimplemented the cpu_pid[] array
    to be dynamically allocated.
  - Added a warning when reading of TRACECMD_OPTION_TIME_SHIFT option
    fails, due to unexpected option's size.
  - Improved loading of TRACECMD_OPTION_GUEST option data, as Steven
    suggested.
 v19 changes:
  - Rebased on top of latest master. The librtacefs is already merged,
    this allows to drop few patches from the set and use librtacefs APIs
    instead.
  - Reimplemented all new trace.dat options to be in binary format,
    instead of text. Leverage the new "trace-cmd dump" sub command to
    track what is written in the file.
  - Addressed Steven's comments.

 v18 changes: addressed Steven Rostdet comments:
  - Replaced semaphores with pthread mutexes.
  - Made bitmask with time sync protocols unlimited, so we can support
    more than 32 protocols. That required to redesign the trace request
    packet format.
  - A lot of small fixes.
	
 v17 changes:
  - Implemented new PTP logic for calculating the clocks offset, using
    histogram of all PTP samples. It gives better results than the logic
    with the fastest response time, so set the new one as default in the
    POC patch.

 v16 changes:
  - Fixed compilation in case no VSOCK is available (Thanks to Slavomir Kaslev)
  - Fixed a typo in trace-cmd-record.1.txt (Thanks to Slavomir Kaslev)
  - Added forgotten file in the patch "trace-cmd: Add new library APIs for
    ftrace instances." - trace-instance.c
  - Fixed few compilation warnings related to TSYNC_DEBUG code.
  - Removed a blank line at the end of "tsync_readme" file. 

 v15 changes:
  - Removed the patch for "--proc-map" from the series, as it should not
    be part of it.

 v14 changes:
  - Bring back the PTP-like algorithm and removed the ftrace event based logic.
  - Reimplemented the PTP-like algorithm to use raw ftrace markers, instead of clock_gettime() API.
  - Refactored the logic to be algorithm independent and plugin friendly.
  - Implemented continuous timestamps synchronization, while the trace is running.
  - Moved logic from trace-cmd application to libtracecmd, as new library APIs.
  - Implemented new trace id functionality.
  - Implemented new guest section in host trace.dat file.
	
 v13 changes:
  - Remove few patches from the set, as they were merged.
  - Rebased to the latest master, Slavomirs patchest "Add VM kernel tracing over
    vsockets and FIFOs" got merged!
 	
 v12 changes:
  - Rebased on top of Slavomir's v13 "Add VM kernel tracing over vsockets and FIFOs"

 v11 changes:
  - Rebased on top of Slavomir's v10 "Add VM kernel tracing over vsockets and FIFOs"
  - Addressed Slavomir's commnents from version 10 of the patch series.

 v10 changes:
  - Fixed broken compilation, call to timestamp_correction_calc() in timestamp_correct
    was smashed.
  - Replaced deprecated tep_data_event_from_type() API with tep_find_event().
  - Fixed a warning on assignment const to non const.

 v9 changes:
  - Fixed implementation of binary search algorithm in timestamp_correct()

 v8 changes:
  - Added rmdir() call in tracecmd_remove_instance(), to completely remove the instance. 
  However, there is an issue with deleting the instances using rmdir(), which is investigated.
  - Few changes in read_qemu_guests_pids(), timestamp_correct(), tsync_offset_load() 
 tracecmd_clock_context_new() and find_raw_events() suggested by Slavomir. 

 v7 changes:
  - Added warning messages in case time synchronization cannot be negotiated or fails.
  - Few optimizations and checks in read_qemu_guests_pids(), tsync_offset_load(),
    and find_raw_events(), suggested by Slavomir Kaslev.
  - Reworked timestamp_correct() to not use static variables.
  - Check TRACECMD_OPTION_TIME_SHIFT before reading time sync samples from the trace.dat file

 v6 changes:
  - Refactored tracecmd_msg_snd_time_sync() and tracecmd_msg_rcv_time_sync() functions:
    removed any time sync calculations logic as separate functions in trace-timesync.c file
  - Defined TSYNC_PROBE, TSYNC_REQ and TSYNC_RESP messages, in order to make the time sync
    protocol comprehensible.
  - Addressed Steven Rostedt comments.
  - Addressed Slavomir Kaslev commnets.

v5 changes:
  - Rebased to Slavomir's v8 "Add VM kernel tracing over vsockets and FIFOs"
    patch series.
  - Implemented an algorithm for time drift correction.
  - Addressed Slavomir's commnets.
  - Refactored the code: moved all time sync specific implementation in trace-timesync.c
  - Isolated all hardcoded event specific stuff in a structure, so it could be easily
    moved to external plugins.
  - Added a check for VSOCK support: do not perform vsock dependent time synchronisation
    in case there is no VSOCK support.

 v4 changes:
  - Removed the implementation of PTP-like algorithm. The current
    logic relies on matching time stamps of kvm_exit/virtio_transport_recv_pkt
    events on host to virtio_transport_alloc_pkt/vp_notify events on guest.
  - Rebased to Slavomir's v7 "Add VM kernel tracing over vsockets and FIFOs"
    patch series.
  - Decreased the time synch probes from 5000 to 300.
  - Addressed Steven Rostedt comments.
  - Code cleanup.

 v3 changes:
 - Removed any magic constants, used in the PTP-like algorithm,
   as Slavomir Kaslev suggested.
 - Implemented new algorithm, based on mapping kvm_exit events
   in host context to vsock_send events in guest context,
   suggested by Steven Rostedt.

 v2 changes:
  - Addressed Steven Rostedt comments.
  - Modified PTP-like timestamps sync algorithm to gain more accuracy, with the
    help of Yordan Karadzhov and Slavomir Kaslev.
]

Tzvetomir Stoyanov (5):
  trace-cmd: Add support for negative time offsets in trace.dat file
  trace-cmd: Find and store pids of tasks, which run virtual CPUs of
    given VM
  trace-cmd: Implement new API tracecmd_add_option_v()
  trace-cmd: Add definitions of htonll() and ntohll()
  trace-cmd: Implement new option in trace.dat file:
    TRACECMD_OPTION_TIME_SHIFT

Tzvetomir Stoyanov (VMware) (10):
  trace-cmd: Add new library API for local CPU count
  trace-cmd: Add new API to generate a unique ID of the tracing session
  trace-cmd: Store the session tracing ID in the trace.dat file
  trace-cmd: Exchange tracing IDs between host and guest
  trace-cmd: Add guest information in host's trace.dat file
  trace-cmd: Add host trace clock as guest trace argument
  trace-cmd: Refactor few trace-cmd internal functions.
  trace-cmd: Basic infrastructure for host - guest timestamp
    synchronization
  trace-cmd: [POC] PTP-like algorithm for host - guest timestamp
    synchronization
  trace-cmd: Debug scripts for PTP-like algorithm for host - guest
    timestamp synchronization

 Documentation/trace-cmd-record.1.txt      |   7 +
 include/trace-cmd/trace-cmd.h             |  84 ++-
 include/traceevent/event-parse.h          |   1 +
 lib/trace-cmd/Makefile                    |   2 +
 lib/trace-cmd/include/trace-cmd-local.h   |  45 +-
 lib/trace-cmd/include/trace-tsync-local.h |  38 ++
 lib/trace-cmd/include/trace-write-local.h |  43 ++
 lib/trace-cmd/trace-input.c               | 337 ++++++++++-
 lib/trace-cmd/trace-msg.c                 | 402 +++++++++++--
 lib/trace-cmd/trace-output.c              | 119 +++-
 lib/trace-cmd/trace-timesync-ptp.c        | 651 ++++++++++++++++++++++
 lib/trace-cmd/trace-timesync.c            | 506 +++++++++++++++++
 lib/trace-cmd/trace-util.c                |  86 +++
 scripts/debug/tsync_hist.py               |  57 ++
 scripts/debug/tsync_readme                |  12 +
 scripts/debug/tsync_res.py                |  46 ++
 tracecmd/Makefile                         |   3 +-
 tracecmd/include/trace-local.h            |  24 +-
 tracecmd/trace-agent.c                    |  59 +-
 tracecmd/trace-dump.c                     | 122 ++++
 tracecmd/trace-profile.c                  |   2 +-
 tracecmd/trace-read.c                     |   4 +-
 tracecmd/trace-record.c                   | 302 +++++++---
 tracecmd/trace-stat.c                     |   4 +-
 tracecmd/trace-tsync.c                    | 272 +++++++++
 tracecmd/trace-usage.c                    |   4 +
 26 files changed, 3037 insertions(+), 195 deletions(-)
 create mode 100644 lib/trace-cmd/include/trace-tsync-local.h
 create mode 100644 lib/trace-cmd/include/trace-write-local.h
 create mode 100644 lib/trace-cmd/trace-timesync-ptp.c
 create mode 100644 lib/trace-cmd/trace-timesync.c
 create mode 100644 scripts/debug/tsync_hist.py
 create mode 100644 scripts/debug/tsync_readme
 create mode 100644 scripts/debug/tsync_res.py
 create mode 100644 tracecmd/trace-tsync.c

-- 
2.24.1

[PATCH v20 01/15] trace-cmd: Add support for negative time offsets in trace.dat file

[Tzvetomir Stoyanov (VMware)]

From: Tzvetomir Stoyanov <tstoyanov@vmware.com>

When synchronizing timestamps between different machines, there are cases
when the time offset is negative. This patch changes the way time offset is
written and read from trace.dat file - as signed decimal, instead of hex.

Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
---
 include/trace-cmd/trace-cmd.h | 2 +-
 lib/trace-cmd/trace-input.c   | 6 +++---
 tracecmd/trace-read.c         | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index a243c250..6763715f 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -161,7 +161,7 @@ const char *tracecmd_buffer_instance_name(struct tracecmd_input *handle, int ind
 struct tracecmd_input *tracecmd_buffer_instance_handle(struct tracecmd_input *handle, int indx);
 int tracecmd_is_buffer_instance(struct tracecmd_input *handle);
 
-void tracecmd_set_ts_offset(struct tracecmd_input *handle, unsigned long long offset);
+void tracecmd_set_ts_offset(struct tracecmd_input *handle, long long offset);
 void tracecmd_set_ts2secs(struct tracecmd_input *handle, unsigned long long hz);
 
 void tracecmd_print_events(struct tracecmd_input *handle, const char *regex);
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index a402f687..842a4c3b 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -93,7 +93,7 @@ struct tracecmd_input {
 	bool			read_page;
 	bool			use_pipe;
 	struct cpu_data 	*cpu_data;
-	unsigned long long	ts_offset;
+	long long		ts_offset;
 	double			ts2secs;
 	char *			cpustats;
 	char *			uname;
@@ -2036,7 +2036,7 @@ static int init_cpu(struct tracecmd_input *handle, int cpu)
 }
 
 void tracecmd_set_ts_offset(struct tracecmd_input *handle,
-			    unsigned long long offset)
+			    long long offset)
 {
 	handle->ts_offset = offset;
 }
@@ -2215,7 +2215,7 @@ tracecmd_search_task_map(struct tracecmd_input *handle,
 
 static int handle_options(struct tracecmd_input *handle)
 {
-	unsigned long long offset;
+	long long offset;
 	unsigned short option;
 	unsigned int size;
 	char *cpustats = NULL;
diff --git a/tracecmd/trace-read.c b/tracecmd/trace-read.c
index 8c2b2ae3..c184c627 100644
--- a/tracecmd/trace-read.c
+++ b/tracecmd/trace-read.c
@@ -58,7 +58,7 @@ static struct list_head handle_list;
 struct input_files {
 	struct list_head	list;
 	const char		*file;
-	unsigned long long	tsoffset;
+	long long		tsoffset;
 	unsigned long long	ts2secs;
 };
 static struct list_head input_files;
@@ -1466,7 +1466,7 @@ void trace_report (int argc, char **argv)
 	struct input_files *inputs;
 	struct handle_list *handles;
 	enum output_type otype;
-	unsigned long long tsoffset = 0;
+	long long tsoffset = 0;
 	unsigned long long ts2secs = 0;
 	unsigned long long ts2sc;
 	int show_stat = 0;
-- 
2.24.1

[PATCH v20 02/15] trace-cmd: Add new library API for local CPU count

[Tzvetomir Stoyanov (VMware)]

In order to reuse the code, the function detecting the
number of local CPU is moved from trace-cmd application to
libtracecmd. The following new library API is introduced:
	int tracecmd_count_cpus(void);

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/trace-cmd/trace-cmd.h  |  3 +++
 lib/trace-cmd/trace-util.c     | 49 ++++++++++++++++++++++++++++++++++
 tracecmd/include/trace-local.h |  2 --
 tracecmd/trace-agent.c         |  2 +-
 tracecmd/trace-profile.c       |  2 +-
 tracecmd/trace-record.c        | 46 +++----------------------------
 tracecmd/trace-stat.c          |  4 +--
 7 files changed, 59 insertions(+), 49 deletions(-)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 6763715f..d1b4a60f 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -409,6 +409,9 @@ void tracecmd_plog(const char *fmt, ...);
 void tracecmd_plog_error(const char *fmt, ...);
 int tracecmd_set_logfile(char *logfile);
 
+/* --- System --- */
+int tracecmd_count_cpus(void);
+
 /* --- Hack! --- */
 int tracecmd_blk_hack(struct tracecmd_input *handle);
 
diff --git a/lib/trace-cmd/trace-util.c b/lib/trace-cmd/trace-util.c
index fc2bcb24..b8841393 100644
--- a/lib/trace-cmd/trace-util.c
+++ b/lib/trace-cmd/trace-util.c
@@ -461,3 +461,52 @@ int tracecmd_stack_tracer_status(int *status)
 	*status = num;
 	return 1; /* full success */
 }
+
+/**
+ * tracecmd_count_cpus - Get the number of CPUs in the system
+ *
+ * Returns the number of CPUs in the system, or 0 in case of an error
+ */
+int tracecmd_count_cpus(void)
+{
+	static int once;
+	char buf[1024];
+	int cpus = 0;
+	char *pbuf;
+	size_t *pn;
+	FILE *fp;
+	size_t n;
+	int r;
+
+	cpus = sysconf(_SC_NPROCESSORS_CONF);
+	if (cpus > 0)
+		return cpus;
+
+	if (!once) {
+		once++;
+		warning("sysconf could not determine number of CPUS");
+	}
+
+	/* Do the hack to figure out # of CPUS */
+	n = 1024;
+	pn = &n;
+	pbuf = buf;
+
+	fp = fopen("/proc/cpuinfo", "r");
+	if (!fp)
+		die("Can not read cpuinfo");
+
+	while ((r = getline(&pbuf, pn, fp)) >= 0) {
+		char *p;
+
+		if (strncmp(buf, "processor", 9) != 0)
+			continue;
+		for (p = buf+9; isspace(*p); p++)
+			;
+		if (*p == ':')
+			cpus++;
+	}
+	fclose(fp);
+
+	return cpus;
+}
diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index 7a0804e2..29f27793 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -247,8 +247,6 @@ void update_first_instance(struct buffer_instance *instance, int topt);
 
 void show_instance_file(struct buffer_instance *instance, const char *name);
 
-int count_cpus(void);
-
 /* moved from trace-cmd.h */
 void tracecmd_create_top_instance(char *name);
 void tracecmd_remove_instances(void);
diff --git a/tracecmd/trace-agent.c b/tracecmd/trace-agent.c
index 93e3edfd..1c6e0a3a 100644
--- a/tracecmd/trace-agent.c
+++ b/tracecmd/trace-agent.c
@@ -203,7 +203,7 @@ static void agent_serve(unsigned int port)
 
 	signal(SIGCHLD, handle_sigchld);
 
-	nr_cpus = count_cpus();
+	nr_cpus = tracecmd_count_cpus();
 	page_size = getpagesize();
 
 	sd = make_vsock(port);
diff --git a/tracecmd/trace-profile.c b/tracecmd/trace-profile.c
index 231e3816..cfae2a22 100644
--- a/tracecmd/trace-profile.c
+++ b/tracecmd/trace-profile.c
@@ -1314,7 +1314,7 @@ void trace_init_profile(struct tracecmd_input *handle, struct hook_list *hook,
 	 * system.
 	 */
 	if (!h->cpus)
-		h->cpus = count_cpus();
+		h->cpus = tracecmd_count_cpus();
 
 	list_head_init(&h->migrate_starts);
 	h->cpu_starts = malloc(sizeof(*h->cpu_starts) * h->cpus);
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 4a49b640..28fe31b7 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -2884,46 +2884,6 @@ static void expand_event_list(void)
 		expand_event_instance(instance);
 }
 
-int count_cpus(void)
-{
-	FILE *fp;
-	char buf[1024];
-	int cpus = 0;
-	char *pbuf;
-	size_t *pn;
-	size_t n;
-	int r;
-
-	cpus = sysconf(_SC_NPROCESSORS_CONF);
-	if (cpus > 0)
-		return cpus;
-
-	warning("sysconf could not determine number of CPUS");
-
-	/* Do the hack to figure out # of CPUS */
-	n = 1024;
-	pn = &n;
-	pbuf = buf;
-
-	fp = fopen("/proc/cpuinfo", "r");
-	if (!fp)
-		die("Can not read cpuinfo");
-
-	while ((r = getline(&pbuf, pn, fp)) >= 0) {
-		char *p;
-
-		if (strncmp(buf, "processor", 9) != 0)
-			continue;
-		for (p = buf+9; isspace(*p); p++)
-			;
-		if (*p == ':')
-			cpus++;
-	}
-	fclose(fp);
-
-	return cpus;
-}
-
 static void finish(int sig)
 {
 	/* all done */
@@ -4608,7 +4568,7 @@ static void reset_clock(void)
 static void reset_cpu_mask(void)
 {
 	struct buffer_instance *instance;
-	int cpus = count_cpus();
+	int cpus = tracecmd_count_cpus();
 	int fullwords = (cpus - 1) / 32;
 	int bits = (cpus - 1) % 32 + 1;
 	int len = (fullwords + 1) * 9;
@@ -5165,7 +5125,7 @@ void init_top_instance(void)
 {
 	if (!top_instance.tracefs)
 		top_instance.tracefs = tracefs_instance_alloc(NULL);
-	top_instance.cpu_count = count_cpus();
+	top_instance.cpu_count = tracecmd_count_cpus();
 	top_instance.flags = BUFFER_FL_KEEP;
 	init_instance(&top_instance);
 }
@@ -5362,7 +5322,7 @@ static void init_common_record_context(struct common_record_context *ctx,
 	memset(ctx, 0, sizeof(*ctx));
 	ctx->instance = &top_instance;
 	ctx->curr_cmd = curr_cmd;
-	local_cpu_count = count_cpus();
+	local_cpu_count = tracecmd_count_cpus();
 	init_top_instance();
 }
 
diff --git a/tracecmd/trace-stat.c b/tracecmd/trace-stat.c
index 0db3baca..3a086a69 100644
--- a/tracecmd/trace-stat.c
+++ b/tracecmd/trace-stat.c
@@ -738,7 +738,7 @@ static void report_cpumask(struct buffer_instance *instance)
 	cont = strstrip(str);
 
 	/* check to make sure all CPUs on this machine are set */
-	cpus = count_cpus();
+	cpus = tracecmd_count_cpus();
 
 	for (i = strlen(cont) - 1; i >= 0 && cpus > 0; i--) {
 		if (cont[i] == ',')
@@ -898,7 +898,7 @@ void trace_stat (int argc, char **argv)
 			instance = create_instance(optarg);
 			if (!instance)
 				die("Failed to create instance");
-			add_instance(instance, count_cpus());
+			add_instance(instance, tracecmd_count_cpus());
 			/* top instance requires direct access */
 			if (!topt && is_top_instance(first_instance))
 				first_instance = instance;
-- 
2.24.1

[PATCH v20 03/15] trace-cmd: Find and store pids of tasks, which run virtual CPUs of given VM

[Tzvetomir Stoyanov (VMware)]

From: Tzvetomir Stoyanov <tstoyanov@vmware.com>

In order to match host and guest events, a mapping between guest VCPU
and the host task, running this VCPU is needed. Extended existing
struct guest to hold such mapping and added logic in read_qemu_guests()
function to initialize it. Implemented a new internal API,
get_guest_vcpu_pid(), to retrieve VCPU-task mapping for given VM.

Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
---
 tracecmd/include/trace-local.h |  2 +
 tracecmd/trace-record.c        | 77 ++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)

diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index 29f27793..a5cf0640 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -247,6 +247,8 @@ void update_first_instance(struct buffer_instance *instance, int topt);
 
 void show_instance_file(struct buffer_instance *instance, const char *name);
 
+int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu);
+
 /* moved from trace-cmd.h */
 void tracecmd_create_top_instance(char *name);
 void tracecmd_remove_instances(void);
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 28fe31b7..4370c964 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -3035,11 +3035,30 @@ struct guest {
 	char *name;
 	int cid;
 	int pid;
+	int cpu_max;
+	int *cpu_pid;
 };
 
 static struct guest *guests;
 static size_t guests_len;
 
+static int set_vcpu_pid_mapping(struct guest *guest, int cpu, int pid)
+{
+	int *cpu_pid;
+
+	if (cpu < 0 || pid < 0)
+		return -1;
+	if (cpu >= guest->cpu_max) {
+		cpu_pid = realloc(guest->cpu_pid, (cpu + 1) * sizeof(int));
+		if (!cpu_pid)
+			return -1;
+		guest->cpu_max = cpu + 1;
+		guest->cpu_pid = cpu_pid;
+	}
+	guest->cpu_pid[cpu] = pid;
+	return 0;
+}
+
 static char *get_qemu_guest_name(char *arg)
 {
 	char *tok, *end = arg;
@@ -3052,6 +3071,46 @@ static char *get_qemu_guest_name(char *arg)
 	return arg;
 }
 
+static void read_qemu_guests_pids(char *guest_task, struct guest *guest)
+{
+	struct dirent *entry;
+	char path[PATH_MAX];
+	char *buf = NULL;
+	size_t n = 0;
+	long int vcpu;
+	long int pid;
+	DIR *dir;
+	FILE *f;
+
+	snprintf(path, sizeof(path), "/proc/%s/task", guest_task);
+	dir = opendir(path);
+	if (!dir)
+		return;
+
+	while ((entry = readdir(dir))) {
+		if (!(entry->d_type == DT_DIR && is_digits(entry->d_name)))
+			continue;
+
+		snprintf(path, sizeof(path), "/proc/%s/task/%s/comm",
+			 guest_task, entry->d_name);
+		f = fopen(path, "r");
+		if (!f)
+			continue;
+
+		if (getline(&buf, &n, f) >= 0 &&
+		    strncmp(buf, "CPU ", 4) == 0) {
+			vcpu = strtol(buf + 4, NULL, 10);
+			pid = strtol(entry->d_name, NULL, 10);
+			if (vcpu < INT_MAX && pid < INT_MAX &&
+			    vcpu >= 0 && pid >= 0)
+				set_vcpu_pid_mapping(guest, vcpu, pid);
+		}
+
+		fclose(f);
+	}
+	free(buf);
+}
+
 static void read_qemu_guests(void)
 {
 	static bool initialized;
@@ -3115,6 +3174,8 @@ static void read_qemu_guests(void)
 		if (!is_qemu)
 			goto next;
 
+		read_qemu_guests_pids(entry->d_name, &guest);
+
 		guests = realloc(guests, (guests_len + 1) * sizeof(*guests));
 		if (!guests)
 			die("Can not allocate guest buffer");
@@ -3160,6 +3221,22 @@ static char *parse_guest_name(char *guest, int *cid, int *port)
 	return guest;
 }
 
+int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu)
+{
+	int i;
+
+	if (!guests)
+		return -1;
+
+	for (i = 0; i < guests_len; i++) {
+		if (!guests[i].cpu_pid || guest_vcpu >= guests[i].cpu_max)
+			continue;
+		if (guest_cid == guests[i].cid)
+			return guests[i].cpu_pid[guest_vcpu];
+	}
+	return -1;
+}
+
 static void set_prio(int prio)
 {
 	struct sched_param sp;
-- 
2.24.1

[PATCH v20 04/15] trace-cmd: Implement new API tracecmd_add_option_v()

[Tzvetomir Stoyanov (VMware)]

From: Tzvetomir Stoyanov <tstoyanov@vmware.com>

A new tracecmd API tracecmd_add_option_v() is introduced.
It adds new option in trace.dat, similar to tracecmd_add_option(),
but the option's data is passed as list of buffers. The standard
struct iovec is used as input parameter, containing the option's
data buffers.

Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
---
 include/trace-cmd/trace-cmd.h    |   5 ++
 include/traceevent/event-parse.h |   1 +
 lib/trace-cmd/trace-output.c     | 117 +++++++++++++++++++++++++++----
 3 files changed, 108 insertions(+), 15 deletions(-)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index d1b4a60f..b6393a89 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -278,11 +278,16 @@ struct tracecmd_output *tracecmd_create_init_file_override(const char *output_fi
 struct tracecmd_option *tracecmd_add_option(struct tracecmd_output *handle,
 					    unsigned short id, int size,
 					    const void *data);
+struct tracecmd_option *
+tracecmd_add_option_v(struct tracecmd_output *handle,
+		      unsigned short id, const struct iovec *vector, int count);
+
 struct tracecmd_option *tracecmd_add_buffer_option(struct tracecmd_output *handle,
 						   const char *name, int cpus);
 
 int tracecmd_write_cpus(struct tracecmd_output *handle, int cpus);
 int tracecmd_write_options(struct tracecmd_output *handle);
+int tracecmd_append_options(struct tracecmd_output *handle);
 int tracecmd_update_option(struct tracecmd_output *handle,
 			   struct tracecmd_option *option, int size,
 			   const void *data);
diff --git a/include/traceevent/event-parse.h b/include/traceevent/event-parse.h
index 52bafa54..cfab6005 100644
--- a/include/traceevent/event-parse.h
+++ b/include/traceevent/event-parse.h
@@ -11,6 +11,7 @@
 #include <stdio.h>
 #include <regex.h>
 #include <string.h>
+#include <sys/uio.h>
 
 #include "traceevent/trace-seq.h"
 
diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index a3dda270..acdd2d57 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -951,21 +951,27 @@ static struct tracecmd_output *create_file(const char *output_file,
 }
 
 /**
- * tracecmd_add_option - add options to the file
+ * tracecmd_add_option_v - add options to the file
  * @handle: the output file handle name
  * @id: the id of the option
  * @size: the size of the option data
- * @data: the data to write to the file.
+ * @data: the data to write to the file
+ * @vector: array of vectors, pointing to the data to write in the file
+ * @count: number of items in the vector array
+ *
  *
  * Returns handle to update option if needed.
  *  Just the content can be updated, with smaller or equal to
  *  content than the specified size.
  */
 struct tracecmd_option *
-tracecmd_add_option(struct tracecmd_output *handle,
-		    unsigned short id, int size, const void *data)
+tracecmd_add_option_v(struct tracecmd_output *handle,
+		      unsigned short id, const struct iovec *vector, int count)
+
 {
 	struct tracecmd_option *option;
+	char *data = NULL;
+	int i, size = 0;
 
 	/*
 	 * We can only add options before they were written.
@@ -974,32 +980,63 @@ tracecmd_add_option(struct tracecmd_output *handle,
 	if (handle->options_written)
 		return NULL;
 
-	handle->nr_options++;
+	for (i = 0; i < count; i++)
+		size += vector[i].iov_len;
+	/* Some IDs (like TRACECMD_OPTION_TRACECLOCK) pass vector with 0 / NULL data */
+	if (size) {
+		data = malloc(size);
+		if (!data) {
+			warning("Insufficient memory");
+			return NULL;
+		}
+	}
 
 	option = malloc(sizeof(*option));
 	if (!option) {
 		warning("Could not allocate space for option");
+		free(data);
 		return NULL;
 	}
 
-	option->id = id;
-	option->size = size;
-	option->data = malloc(size);
-	if (!option->data) {
-		warning("Insufficient memory");
-		free(option);
-		return NULL;
+	handle->nr_options++;
+	option->data = data;
+	for (i = 0; i < count; i++) {
+		if (vector[i].iov_base && vector[i].iov_len) {
+			memcpy(data, vector[i].iov_base, vector[i].iov_len);
+			data += vector[i].iov_len;
+		}
 	}
 
-	/* Some IDs (like TRACECMD_OPTION_TRACECLOCK) pass 0 / NULL data */
-	if (size)
-		memcpy(option->data, data, size);
+	option->size = size;
+	option->id = id;
 
 	list_add_tail(&option->list, &handle->options);
 
 	return option;
 }
 
+/**
+ * tracecmd_add_option - add options to the file
+ * @handle: the output file handle name
+ * @id: the id of the option
+ * @size: the size of the option data
+ * @data: the data to write to the file
+ *
+ * Returns handle to update option if needed
+ *  Just the content can be updated, with smaller or equal to
+ *  content than the specified size
+ */
+struct tracecmd_option *
+tracecmd_add_option(struct tracecmd_output *handle,
+		    unsigned short id, int size, const void *data)
+{
+	struct iovec vect;
+
+	vect.iov_base = (void *) data;
+	vect.iov_len = size;
+	return tracecmd_add_option_v(handle, id, &vect, 1);
+}
+
 int tracecmd_write_cpus(struct tracecmd_output *handle, int cpus)
 {
 	cpus = convert_endian_4(handle, cpus);
@@ -1047,6 +1084,56 @@ int tracecmd_write_options(struct tracecmd_output *handle)
 	return 0;
 }
 
+int tracecmd_append_options(struct tracecmd_output *handle)
+{
+	struct tracecmd_option *options;
+	unsigned short option;
+	unsigned short endian2;
+	unsigned int endian4;
+	off_t offset;
+	int r;
+
+	/* If already written, ignore */
+	if (handle->options_written)
+		return 0;
+
+	if (lseek64(handle->fd, 0, SEEK_END) == (off_t)-1)
+		return -1;
+	offset = lseek64(handle->fd, -2, SEEK_CUR);
+	if (offset == (off_t)-1)
+		return -1;
+
+	r = pread(handle->fd, &option, 2, offset);
+	if (r != 2 || option != TRACECMD_OPTION_DONE)
+		return -1;
+
+	list_for_each_entry(options, &handle->options, list) {
+		endian2 = convert_endian_2(handle, options->id);
+		if (do_write_check(handle, &endian2, 2))
+			return -1;
+
+		endian4 = convert_endian_4(handle, options->size);
+		if (do_write_check(handle, &endian4, 4))
+			return -1;
+
+		/* Save the data location in case it needs to be updated */
+		options->offset = lseek64(handle->fd, 0, SEEK_CUR);
+
+		if (do_write_check(handle, options->data,
+				   options->size))
+			return -1;
+	}
+
+	option = TRACECMD_OPTION_DONE;
+
+	if (do_write_check(handle, &option, 2))
+		return -1;
+
+	handle->options_written = 1;
+
+	return 0;
+}
+
 int tracecmd_update_option(struct tracecmd_output *handle,
 			   struct tracecmd_option *option, int size,
 			   const void *data)
-- 
2.24.1

[PATCH v20 05/15] trace-cmd: Add new API to generate a unique ID of the tracing session

[Tzvetomir Stoyanov (VMware)]

A new libtracecmd API is implemented:
	unsigned long long tracecmd_generate_traceid(void);
At trace-cmd init phase a unique ID, used for the current tracing session.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/trace-cmd/trace-cmd.h  |  1 +
 lib/trace-cmd/trace-util.c     | 37 ++++++++++++++++++++++++++++++++++
 tracecmd/include/trace-local.h |  1 +
 tracecmd/trace-record.c        |  1 +
 4 files changed, 40 insertions(+)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index b6393a89..7519e82a 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -415,6 +415,7 @@ void tracecmd_plog_error(const char *fmt, ...);
 int tracecmd_set_logfile(char *logfile);
 
 /* --- System --- */
+unsigned long long tracecmd_generate_traceid(void);
 int tracecmd_count_cpus(void);
 
 /* --- Hack! --- */
diff --git a/lib/trace-cmd/trace-util.c b/lib/trace-cmd/trace-util.c
index b8841393..04dc804c 100644
--- a/lib/trace-cmd/trace-util.c
+++ b/lib/trace-cmd/trace-util.c
@@ -18,6 +18,8 @@
 #include <sys/mount.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/sysinfo.h>
+#include <time.h>
 
 #include "trace-cmd.h"
 #include "event-utils.h"
@@ -510,3 +512,38 @@ int tracecmd_count_cpus(void)
 
 	return cpus;
 }
+
+#define FNV_64_PRIME 0x100000001b3ULL
+/*
+ * tracecmd_generate_traceid - Generate a unique ID, used to identify
+ *			       the current tracing session
+ *
+ * Returns unique ID
+ */
+unsigned long long tracecmd_generate_traceid(void)
+{
+	unsigned long long hash = 0;
+	unsigned char *ustr;
+	struct sysinfo sinfo;
+	struct timespec ts;
+	char *str = NULL;
+
+	clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
+	sysinfo(&sinfo);
+	asprintf(&str, "%ld %ld %ld %ld %ld %ld %ld %ld %d",
+		 ts.tv_sec, ts.tv_nsec,
+		 sinfo.loads[0], sinfo.loads[1], sinfo.loads[2],
+		 sinfo.freeram, sinfo.sharedram, sinfo.freeswap,
+		 sinfo.procs);
+	if (!str)
+		return 0;
+	ustr = (unsigned char *)str;
+	hash = 0;
+	while (*ustr) {
+		hash ^= (unsigned long long)*ustr++;
+		hash *= FNV_64_PRIME;
+	}
+
+	free(str);
+	return hash;
+}
diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index a5cf0640..6fe22bb0 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -185,6 +185,7 @@ struct pid_addr_maps {
 struct buffer_instance {
 	struct buffer_instance	*next;
 	struct tracefs_instance	*tracefs;
+	unsigned long long	trace_id;
 	char			*cpumask;
 	struct event_list	*events;
 	struct event_list	**event_next;
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 4370c964..5d31cad8 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -5204,6 +5204,7 @@ void init_top_instance(void)
 		top_instance.tracefs = tracefs_instance_alloc(NULL);
 	top_instance.cpu_count = tracecmd_count_cpus();
 	top_instance.flags = BUFFER_FL_KEEP;
+	top_instance.trace_id = tracecmd_generate_traceid();
 	init_instance(&top_instance);
 }
 
-- 
2.24.1

[PATCH v20 06/15] trace-cmd: Store the session tracing ID in the trace.dat file

[Tzvetomir Stoyanov (VMware)]

The ID of the current tracing session is stored in the trace.dat file.
A new file option is introduced:
	TRACECMD_OPTION_TRACEID
The data is stored in the file as unsigned long long integer
A new libtracecmd API is introduced, to get the ID when the trace.dat file is read:
	unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle);

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/trace-cmd/trace-cmd.h |  2 ++
 lib/trace-cmd/trace-input.c   | 16 ++++++++++++++++
 tracecmd/trace-dump.c         | 11 +++++++++++
 tracecmd/trace-record.c       |  9 +++++++++
 4 files changed, 38 insertions(+)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 7519e82a..6075a37e 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -109,6 +109,7 @@ enum {
 	TRACECMD_OPTION_CPUCOUNT,
 	TRACECMD_OPTION_VERSION,
 	TRACECMD_OPTION_PROCMAPS,
+	TRACECMD_OPTION_TRACEID,
 };
 
 enum {
@@ -151,6 +152,7 @@ int tracecmd_copy_headers(struct tracecmd_input *handle, int fd);
 void tracecmd_set_flag(struct tracecmd_input *handle, int flag);
 void tracecmd_clear_flag(struct tracecmd_input *handle, int flag);
 unsigned long tracecmd_get_flags(struct tracecmd_input *handle);
+unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle);
 
 void tracecmd_parse_trace_clock(struct tracecmd_input *handle, char *file, int size);
 
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index 842a4c3b..aca13c4e 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -82,6 +82,7 @@ struct tracecmd_input {
 	struct tep_plugin_list	*plugin_list;
 	struct tracecmd_input	*parent;
 	unsigned long		flags;
+	unsigned long long	trace_id;
 	int			fd;
 	int			long_size;
 	int			page_size;
@@ -2316,6 +2317,10 @@ static int handle_options(struct tracecmd_input *handle)
 			if (buf[size-1] == '\0')
 				trace_pid_map_load(handle, buf);
 			break;
+		case TRACECMD_OPTION_TRACEID:
+			handle->trace_id = tep_read_number(handle->pevent,
+							   &cpus, 8);
+			break;
 		default:
 			warning("unknown option %d", option);
 			break;
@@ -3419,3 +3424,14 @@ void tracecmd_set_show_data_func(struct tracecmd_input *handle,
 {
 	handle->show_data_func = func;
 }
+
+/**
+ * tracecmd_get_traceid - get the trace id of the session
+ * @handle: input handle for the trace.dat file
+ *
+ * Returns the trace id, written in the trace file
+ */
+unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle)
+{
+	return handle->trace_id;
+}
diff --git a/tracecmd/trace-dump.c b/tracecmd/trace-dump.c
index 415e9138..2dfeaa0f 100644
--- a/tracecmd/trace-dump.c
+++ b/tracecmd/trace-dump.c
@@ -358,6 +358,14 @@ static void dump_option_int(int fd, int size, char *desc)
 	do_print(OPTIONS, "%d\n", val);
 }
 
+static void dump_option_xlong(int fd, int size, char *desc)
+{
+	long long val;
+
+	do_print(OPTIONS, "\t\t[Option %s, %d bytes]\n", desc, size);
+	read_file_number(fd, &val, size);
+	do_print(OPTIONS, "0x%llX\n", val);
+}
 static void dump_options(int fd)
 {
 	unsigned short option;
@@ -408,6 +416,9 @@ static void dump_options(int fd)
 		case TRACECMD_OPTION_PROCMAPS:
 			dump_option_string(fd, size, "PROCMAPS");
 			break;
+		case TRACECMD_OPTION_TRACEID:
+			dump_option_xlong(fd, size, "TRACEID");
+			break;
 		default:
 			do_print(OPTIONS, " %d %d\t[Unknown option, size - skipping]\n",
 				 option, size);
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 5d31cad8..3e24eb43 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -3895,6 +3895,13 @@ add_pid_maps(struct tracecmd_output *handle, struct buffer_instance *instance)
 	trace_seq_destroy(&s);
 }
 
+static void
+add_trace_id(struct tracecmd_output *handle, struct buffer_instance *instance)
+{
+	tracecmd_add_option(handle, TRACECMD_OPTION_TRACEID,
+			    sizeof(long long), &instance->trace_id);
+}
+
 static void
 add_buffer_stat(struct tracecmd_output *handle, struct buffer_instance *instance)
 {
@@ -4000,6 +4007,8 @@ static void add_options(struct tracecmd_output *handle, struct common_record_con
 	add_option_hooks(handle);
 	add_uname(handle);
 	add_version(handle);
+	if (!no_top_instance())
+		add_trace_id(handle, &top_instance);
 }
 
 static void write_guest_file(struct buffer_instance *instance)
-- 
2.24.1

[PATCH v20 07/15] trace-cmd: Add definitions of htonll() and ntohll()

[Tzvetomir Stoyanov (VMware)]

From: Tzvetomir Stoyanov <tstoyanov@vmware.com>

Reorganized libtracecmd internal headers:
 - Renamed trace-cmd-local.h to trace-write-local.h
This internal header implements static __do_write_check() function,
used in trace-input.c, trace-output.c and trace-msg.c files.
The header cannot be included in other files, which do not call
__do_write_check(). The new name trace-write-local.h reflects more
closely the purpose of the file.
 - Added trace-cmd-local.h file, to share code inside libtracecmd.
 - Added definitions of htonll() and ntohll(), if not already defined, in
trace-cmd-local.h

Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
---
 lib/trace-cmd/include/trace-cmd-local.h   | 45 ++++++-----------------
 lib/trace-cmd/include/trace-write-local.h | 43 ++++++++++++++++++++++
 lib/trace-cmd/trace-input.c               |  2 +-
 lib/trace-cmd/trace-msg.c                 |  2 +-
 lib/trace-cmd/trace-output.c              |  2 +
 5 files changed, 58 insertions(+), 36 deletions(-)
 create mode 100644 lib/trace-cmd/include/trace-write-local.h

diff --git a/lib/trace-cmd/include/trace-cmd-local.h b/lib/trace-cmd/include/trace-cmd-local.h
index 09574dbd..95dce66c 100644
--- a/lib/trace-cmd/include/trace-cmd-local.h
+++ b/lib/trace-cmd/include/trace-cmd-local.h
@@ -6,10 +6,8 @@
 #ifndef _TRACE_CMD_LOCAL_H
 #define _TRACE_CMD_LOCAL_H
 
-/* Local for trace-input.c and trace-output.c */
-
-#include "trace-cmd.h"
-#include "event-utils.h"
+/* Can be overridden */
+void warning(const char *fmt, ...);
 
 /* trace.dat file format version */
 #define FILE_VERSION 6
@@ -18,36 +16,15 @@
 #define STR(x)	_STR(x)
 #define FILE_VERSION_STRING STR(FILE_VERSION)
 
-static ssize_t __do_write(int fd, const void *data, size_t size)
-{
-	ssize_t tot = 0;
-	ssize_t w;
-
-	do {
-		w = write(fd, data + tot, size - tot);
-		tot += w;
-
-		if (!w)
-			break;
-		if (w < 0)
-			return w;
-	} while (tot != size);
-
-	return tot;
-}
-
-static ssize_t
-__do_write_check(int fd, const void *data, size_t size)
-{
-	ssize_t ret;
-
-	ret = __do_write(fd, data, size);
-	if (ret < 0)
-		return ret;
-	if (ret != size)
-		return -1;
+#ifndef htonll
+# if __BYTE_ORDER == __LITTLE_ENDIAN
+#define htonll(x) __bswap_64(x)
+#define ntohll(x) __bswap_64(x)
+#else
+#define htonll(x) (x)
+#define ntohll(x) (x)
+#endif
+#endif
 
-	return 0;
-}
 
 #endif /* _TRACE_CMD_LOCAL_H */
diff --git a/lib/trace-cmd/include/trace-write-local.h b/lib/trace-cmd/include/trace-write-local.h
new file mode 100644
index 00000000..94ad910b
--- /dev/null
+++ b/lib/trace-cmd/include/trace-write-local.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: LGPL-2.1 */
+/*
+ * Copyright (C) 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+#ifndef _TRACE_WRITE_LOCAL_H
+#define _TRACE_WRITE_LOCAL_H
+
+/* Local for trace-input.c, trace-output.c and trace-msg.c */
+
+static ssize_t __do_write(int fd, const void *data, size_t size)
+{
+	ssize_t tot = 0;
+	ssize_t w;
+
+	do {
+		w = write(fd, data + tot, size - tot);
+		tot += w;
+
+		if (!w)
+			break;
+		if (w < 0)
+			return w;
+	} while (tot != size);
+
+	return tot;
+}
+
+static ssize_t
+__do_write_check(int fd, const void *data, size_t size)
+{
+	ssize_t ret;
+
+	ret = __do_write(fd, data, size);
+	if (ret < 0)
+		return ret;
+	if (ret != size)
+		return -1;
+
+	return 0;
+}
+
+#endif /* _TRACE_WRITE_LOCAL_H */
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index aca13c4e..f5611b46 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -15,7 +15,7 @@
 
 #include <linux/time64.h>
 
-#include "trace-cmd-local.h"
+#include "trace-write-local.h"
 #include "trace-local.h"
 #include "kbuffer.h"
 #include "list.h"
diff --git a/lib/trace-cmd/trace-msg.c b/lib/trace-cmd/trace-msg.c
index 9c8a6908..85a2bae6 100644
--- a/lib/trace-cmd/trace-msg.c
+++ b/lib/trace-cmd/trace-msg.c
@@ -22,7 +22,7 @@
 #include <sys/types.h>
 #include <linux/types.h>
 
-#include "trace-cmd-local.h"
+#include "trace-write-local.h"
 #include "trace-local.h"
 #include "trace-msg.h"
 
diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index acdd2d57..4a9a857d 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -21,7 +21,9 @@
 #include <glob.h>
 
 #include "tracefs.h"
+#include "trace-cmd.h"
 #include "trace-cmd-local.h"
+#include "trace-write-local.h"
 #include "list.h"
 #include "trace-msg.h"
 
-- 
2.24.1

[PATCH v20 08/15] trace-cmd: Exchange tracing IDs between host and guest

[Tzvetomir Stoyanov (VMware)]

Extend the trace request and trace reply messages, to include also
the IDs of host and guest tracing sessions. Those IDs are used to
unambiguously match the tracing sessions, when reading trace.dat files.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/trace-cmd/trace-cmd.h  | 12 ++++++++----
 lib/trace-cmd/trace-msg.c      | 31 ++++++++++++++++++++++---------
 tracecmd/include/trace-local.h |  3 ++-
 tracecmd/trace-agent.c         | 10 +++++++---
 tracecmd/trace-record.c        | 10 +++++++---
 5 files changed, 46 insertions(+), 20 deletions(-)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 6075a37e..55abd489 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -370,16 +370,20 @@ bool tracecmd_msg_done(struct tracecmd_msg_handle *msg_handle);
 void tracecmd_msg_set_done(struct tracecmd_msg_handle *msg_handle);
 
 int tracecmd_msg_send_trace_req(struct tracecmd_msg_handle *msg_handle,
-				int argc, char **argv, bool use_fifos);
+				int argc, char **argv, bool use_fifos,
+				unsigned long long trace_id);
 int tracecmd_msg_recv_trace_req(struct tracecmd_msg_handle *msg_handle,
-				int *argc, char ***argv, bool *use_fifos);
+				int *argc, char ***argv, bool *use_fifos,
+				unsigned long long *trace_id);
 
 int tracecmd_msg_send_trace_resp(struct tracecmd_msg_handle *msg_handle,
 				 int nr_cpus, int page_size,
-				 unsigned int *ports, bool use_fifos);
+				 unsigned int *ports, bool use_fifos,
+				 unsigned long long trace_id);
 int tracecmd_msg_recv_trace_resp(struct tracecmd_msg_handle *msg_handle,
 				 int *nr_cpus, int *page_size,
-				 unsigned int **ports, bool *use_fifos);
+				 unsigned int **ports, bool *use_fifos,
+				 unsigned long long *trace_id);
 
 /* --- Plugin handling --- */
 extern struct tep_plugin_option trace_ftrace_options[];
diff --git a/lib/trace-cmd/trace-msg.c b/lib/trace-cmd/trace-msg.c
index 85a2bae6..d6a68ac3 100644
--- a/lib/trace-cmd/trace-msg.c
+++ b/lib/trace-cmd/trace-msg.c
@@ -23,6 +23,7 @@
 #include <linux/types.h>
 
 #include "trace-write-local.h"
+#include "trace-cmd-local.h"
 #include "trace-local.h"
 #include "trace-msg.h"
 
@@ -63,12 +64,14 @@ struct tracecmd_msg_rinit {
 struct tracecmd_msg_trace_req {
 	be32 flags;
 	be32 argc;
+	u64 trace_id;
 } __attribute__((packed));
 
 struct tracecmd_msg_trace_resp {
 	be32 flags;
 	be32 cpus;
 	be32 page_size;
+	u64 trace_id;
 } __attribute__((packed));
 
 struct tracecmd_msg_header {
@@ -811,7 +814,8 @@ int tracecmd_msg_wait_close_resp(struct tracecmd_msg_handle *msg_handle)
 	return tracecmd_msg_wait_for_cmd(msg_handle, MSG_CLOSE_RESP);
 }
 
-static int make_trace_req(struct tracecmd_msg *msg, int argc, char **argv, bool use_fifos)
+static int make_trace_req(struct tracecmd_msg *msg, int argc, char **argv,
+			  bool use_fifos, unsigned long long trace_id)
 {
 	size_t args_size = 0;
 	char *p;
@@ -823,6 +827,7 @@ static int make_trace_req(struct tracecmd_msg *msg, int argc, char **argv, bool
 	msg->hdr.size = htonl(ntohl(msg->hdr.size) + args_size);
 	msg->trace_req.flags = use_fifos ? htonl(MSG_TRACE_USE_FIFOS) : htonl(0);
 	msg->trace_req.argc = htonl(argc);
+	msg->trace_req.trace_id = htonll(trace_id);
 	msg->buf = calloc(args_size, 1);
 	if (!msg->buf)
 		return -ENOMEM;
@@ -835,13 +840,14 @@ static int make_trace_req(struct tracecmd_msg *msg, int argc, char **argv, bool
 }
 
 int tracecmd_msg_send_trace_req(struct tracecmd_msg_handle *msg_handle,
-				int argc, char **argv, bool use_fifos)
+				int argc, char **argv, bool use_fifos,
+				unsigned long long trace_id)
 {
 	struct tracecmd_msg msg;
 	int ret;
 
 	tracecmd_msg_init(MSG_TRACE_REQ, &msg);
-	ret = make_trace_req(&msg, argc, argv, use_fifos);
+	ret = make_trace_req(&msg, argc, argv, use_fifos, trace_id);
 	if (ret < 0)
 		return ret;
 
@@ -854,7 +860,8 @@ int tracecmd_msg_send_trace_req(struct tracecmd_msg_handle *msg_handle,
   *     free(argv);
   */
 int tracecmd_msg_recv_trace_req(struct tracecmd_msg_handle *msg_handle,
-				int *argc, char ***argv, bool *use_fifos)
+				int *argc, char ***argv, bool *use_fifos,
+				unsigned long long *trace_id)
 {
 	struct tracecmd_msg msg;
 	char *p, *buf_end, **args;
@@ -901,7 +908,7 @@ int tracecmd_msg_recv_trace_req(struct tracecmd_msg_handle *msg_handle,
 	*argc = nr_args;
 	*argv = args;
 	*use_fifos = ntohl(msg.trace_req.flags) & MSG_TRACE_USE_FIFOS;
-
+	*trace_id = ntohll(msg.trace_req.trace_id);
 	/*
 	 * On success we're passing msg.buf to the caller through argv[0] so we
 	 * reset it here before calling msg_free().
@@ -921,7 +928,8 @@ out:
 }
 
 static int make_trace_resp(struct tracecmd_msg *msg, int page_size, int nr_cpus,
-			   unsigned int *ports, bool use_fifos)
+			   unsigned int *ports, bool use_fifos,
+			   unsigned long long trace_id)
 {
 	int data_size;
 
@@ -935,19 +943,22 @@ static int make_trace_resp(struct tracecmd_msg *msg, int page_size, int nr_cpus,
 	msg->trace_resp.flags = use_fifos ? htonl(MSG_TRACE_USE_FIFOS) : htonl(0);
 	msg->trace_resp.cpus = htonl(nr_cpus);
 	msg->trace_resp.page_size = htonl(page_size);
+	msg->trace_resp.trace_id = htonll(trace_id);
 
 	return 0;
 }
 
 int tracecmd_msg_send_trace_resp(struct tracecmd_msg_handle *msg_handle,
 				 int nr_cpus, int page_size,
-				 unsigned int *ports, bool use_fifos)
+				 unsigned int *ports, bool use_fifos,
+				 unsigned long long trace_id)
 {
 	struct tracecmd_msg msg;
 	int ret;
 
 	tracecmd_msg_init(MSG_TRACE_RESP, &msg);
-	ret = make_trace_resp(&msg, page_size, nr_cpus, ports, use_fifos);
+	ret = make_trace_resp(&msg, page_size, nr_cpus, ports,
+			      use_fifos, trace_id);
 	if (ret < 0)
 		return ret;
 
@@ -956,7 +967,8 @@ int tracecmd_msg_send_trace_resp(struct tracecmd_msg_handle *msg_handle,
 
 int tracecmd_msg_recv_trace_resp(struct tracecmd_msg_handle *msg_handle,
 				 int *nr_cpus, int *page_size,
-				 unsigned int **ports, bool *use_fifos)
+				 unsigned int **ports, bool *use_fifos,
+				 unsigned long long *trace_id)
 {
 	struct tracecmd_msg msg;
 	char *p, *buf_end;
@@ -981,6 +993,7 @@ int tracecmd_msg_recv_trace_resp(struct tracecmd_msg_handle *msg_handle,
 	*use_fifos = ntohl(msg.trace_resp.flags) & MSG_TRACE_USE_FIFOS;
 	*nr_cpus = ntohl(msg.trace_resp.cpus);
 	*page_size = ntohl(msg.trace_resp.page_size);
+	*trace_id = ntohll(msg.trace_resp.trace_id);
 	*ports = calloc(*nr_cpus, sizeof(**ports));
 	if (!*ports) {
 		ret = -ENOMEM;
diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index 6fe22bb0..4f2b5541 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -101,7 +101,8 @@ void trace_dump(int argc, char **argv);
 
 int trace_record_agent(struct tracecmd_msg_handle *msg_handle,
 		       int cpus, int *fds,
-		       int argc, char **argv, bool use_fifos);
+		       int argc, char **argv, bool use_fifos,
+		       unsigned long long trace_id);
 
 struct hook_list;
 
diff --git a/tracecmd/trace-agent.c b/tracecmd/trace-agent.c
index 1c6e0a3a..52d27195 100644
--- a/tracecmd/trace-agent.c
+++ b/tracecmd/trace-agent.c
@@ -128,6 +128,7 @@ cleanup:
 static void agent_handle(int sd, int nr_cpus, int page_size)
 {
 	struct tracecmd_msg_handle *msg_handle;
+	unsigned long long trace_id;
 	unsigned int *ports;
 	char **argv = NULL;
 	int argc = 0;
@@ -144,7 +145,8 @@ static void agent_handle(int sd, int nr_cpus, int page_size)
 	if (!msg_handle)
 		die("Failed to allocate message handle");
 
-	ret = tracecmd_msg_recv_trace_req(msg_handle, &argc, &argv, &use_fifos);
+	ret = tracecmd_msg_recv_trace_req(msg_handle, &argc, &argv,
+					  &use_fifos, &trace_id);
 	if (ret < 0)
 		die("Failed to receive trace request");
 
@@ -154,12 +156,14 @@ static void agent_handle(int sd, int nr_cpus, int page_size)
 	if (!use_fifos)
 		make_vsocks(nr_cpus, fds, ports);
 
+	trace_id = tracecmd_generate_traceid();
 	ret = tracecmd_msg_send_trace_resp(msg_handle, nr_cpus, page_size,
-					   ports, use_fifos);
+					   ports, use_fifos, trace_id);
 	if (ret < 0)
 		die("Failed to send trace response");
 
-	trace_record_agent(msg_handle, nr_cpus, fds, argc, argv, use_fifos);
+	trace_record_agent(msg_handle, nr_cpus, fds, argc, argv,
+			   use_fifos, trace_id);
 
 	free(argv[0]);
 	free(argv);
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 3e24eb43..7427fea4 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -3686,12 +3686,14 @@ static void connect_to_agent(struct buffer_instance *instance)
 		die("Failed to allocate message handle");
 
 	ret = tracecmd_msg_send_trace_req(msg_handle, instance->argc,
-					  instance->argv, use_fifos);
+					  instance->argv, use_fifos,
+					  top_instance.trace_id);
 	if (ret < 0)
 		die("Failed to send trace request");
 
 	ret = tracecmd_msg_recv_trace_resp(msg_handle, &nr_cpus, &page_size,
-					   &ports, &use_fifos);
+					   &ports, &use_fifos,
+					   &instance->trace_id);
 	if (ret < 0)
 		die("Failed to receive trace response");
 
@@ -6237,7 +6239,8 @@ void trace_record(int argc, char **argv)
 int trace_record_agent(struct tracecmd_msg_handle *msg_handle,
 		       int cpus, int *fds,
 		       int argc, char **argv,
-		       bool use_fifos)
+		       bool use_fifos,
+		       unsigned long long trace_id)
 {
 	struct common_record_context ctx;
 	char **argv_plus;
@@ -6267,6 +6270,7 @@ int trace_record_agent(struct tracecmd_msg_handle *msg_handle,
 	ctx.instance->flags |= BUFFER_FL_AGENT;
 	ctx.instance->msg_handle = msg_handle;
 	msg_handle->version = V3_PROTOCOL;
+	top_instance.trace_id = trace_id;
 	record_trace(argc, argv, &ctx);
 
 	free(argv_plus);
-- 
2.24.1

[PATCH v20 09/15] trace-cmd: Implement new option in trace.dat file: TRACECMD_OPTION_TIME_SHIFT

[Tzvetomir Stoyanov (VMware)]

From: Tzvetomir Stoyanov <tstoyanov@vmware.com>

The TRACECMD_OPTION_TIME_SHIFT is used when synchronizing trace time stamps between
two trace.dat files. It contains multiple long long (time, offset) pairs, describing
time stamps _offset_, measured in the given local _time_. The content of the option
buffer is:
 8 bytes - long long integer, ID of the tracing session
 4 bytes - integer, count of timestamp offsets
 long long array of size _count_, local time in which the offset is measured
 long long array of size _count_, offset of the time stamps

Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
---
 include/trace-cmd/trace-cmd.h |   3 +
 lib/trace-cmd/trace-input.c   | 185 +++++++++++++++++++++++++++++++++-
 tracecmd/trace-dump.c         |  49 +++++++++
 3 files changed, 235 insertions(+), 2 deletions(-)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 55abd489..ac46637e 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -110,6 +110,7 @@ enum {
 	TRACECMD_OPTION_VERSION,
 	TRACECMD_OPTION_PROCMAPS,
 	TRACECMD_OPTION_TRACEID,
+	TRACECMD_OPTION_TIME_SHIFT,
 };
 
 enum {
@@ -153,6 +154,8 @@ void tracecmd_set_flag(struct tracecmd_input *handle, int flag);
 void tracecmd_clear_flag(struct tracecmd_input *handle, int flag);
 unsigned long tracecmd_get_flags(struct tracecmd_input *handle);
 unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle);
+unsigned long long tracecmd_get_tsync_peer(struct tracecmd_input *handle);
+int tracecmd_enable_tsync(struct tracecmd_input *handle, bool enable);
 
 void tracecmd_parse_trace_clock(struct tracecmd_input *handle, char *file, int size);
 
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index f5611b46..cf7be730 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -77,6 +77,18 @@ struct input_buffer_instance {
 	size_t			offset;
 };
 
+struct ts_offset_sample {
+	long long	time;
+	long long	offset;
+};
+
+struct host_trace_info {
+	bool			sync_enable;
+	unsigned long long	trace_id;
+	int			ts_samples_count;
+	struct ts_offset_sample	*ts_samples;
+};
+
 struct tracecmd_input {
 	struct tep_handle	*pevent;
 	struct tep_plugin_list	*plugin_list;
@@ -95,6 +107,7 @@ struct tracecmd_input {
 	bool			use_pipe;
 	struct cpu_data 	*cpu_data;
 	long long		ts_offset;
+	struct host_trace_info	host;
 	double			ts2secs;
 	char *			cpustats;
 	char *			uname;
@@ -1075,6 +1088,69 @@ static void free_next(struct tracecmd_input *handle, int cpu)
 	free_record(record);
 }
 
+static inline unsigned long long
+timestamp_correction_calc(unsigned long long ts, struct ts_offset_sample *min,
+			  struct ts_offset_sample *max)
+{
+	long long offset = ((long long)ts - min->time) *
+			   (max->offset - min->offset);
+	long long delta = max->time - min->time;
+	long long tscor = min->offset +
+			(offset + delta / 2) / delta;
+
+	if (tscor < 0)
+		return ts - llabs(tscor);
+
+	return ts + tscor;
+}
+
+static unsigned long long timestamp_correct(unsigned long long ts,
+					    struct tracecmd_input *handle)
+{
+	struct host_trace_info	*host = &handle->host;
+	int min, mid, max;
+
+	if (handle->ts_offset)
+		return ts + handle->ts_offset;
+
+	if (!host->sync_enable)
+		return ts;
+
+	/* We have one sample, nothing to calc here */
+	if (host->ts_samples_count == 1)
+		return ts + host->ts_samples[0].offset;
+
+	/* We have two samples, nothing to search here */
+	if (host->ts_samples_count == 2)
+		return timestamp_correction_calc(ts, &host->ts_samples[0],
+						 &host->ts_samples[1]);
+
+	/* We have more than two samples */
+	if (ts <= host->ts_samples[0].time)
+		return timestamp_correction_calc(ts,
+						 &host->ts_samples[0],
+						 &host->ts_samples[1]);
+	else if (ts >= host->ts_samples[host->ts_samples_count-1].time)
+		return timestamp_correction_calc(ts,
+						 &host->ts_samples[host->ts_samples_count-2],
+						 &host->ts_samples[host->ts_samples_count-1]);
+	min = 0;
+	max = host->ts_samples_count-1;
+	mid = (min + max)/2;
+	while (min <= max) {
+		if (ts < host->ts_samples[mid].time)
+			max = mid - 1;
+		else if (ts > host->ts_samples[mid].time)
+			min = mid + 1;
+		else
+			break;
+		mid = (min + max)/2;
+	}
+
+	return timestamp_correction_calc(ts, &host->ts_samples[mid],
+					 &host->ts_samples[mid+1]);
+}
+
 /*
  * Page is mapped, now read in the page header info.
  */
@@ -1096,7 +1172,7 @@ static int update_page_info(struct tracecmd_input *handle, int cpu)
 		    kbuffer_subbuffer_size(kbuf));
 		return -1;
 	}
-	handle->cpu_data[cpu].timestamp = kbuffer_timestamp(kbuf) + handle->ts_offset;
+	handle->cpu_data[cpu].timestamp = timestamp_correct(kbuffer_timestamp(kbuf), handle);
 
 	if (handle->ts2secs)
 		handle->cpu_data[cpu].timestamp *= handle->ts2secs;
@@ -1729,7 +1805,7 @@ read_again:
 		goto read_again;
 	}
 
-	handle->cpu_data[cpu].timestamp = ts + handle->ts_offset;
+	handle->cpu_data[cpu].timestamp = timestamp_correct(ts, handle);
 
 	if (handle->ts2secs) {
 		handle->cpu_data[cpu].timestamp *= handle->ts2secs;
@@ -2052,6 +2128,48 @@ void tracecmd_set_ts2secs(struct tracecmd_input *handle,
 	handle->use_trace_clock = false;
 }
 
+static int tsync_offset_cmp(const void *a, const void *b)
+{
+	struct ts_offset_sample *ts_a = (struct ts_offset_sample *)a;
+	struct ts_offset_sample *ts_b = (struct ts_offset_sample *)b;
+
+	if (ts_a->time > ts_b->time)
+		return 1;
+	if (ts_a->time < ts_b->time)
+		return -1;
+	return 0;
+}
+
+static void tsync_offset_load(struct tracecmd_input *handle, char *buf)
+{
+	struct host_trace_info *host = &handle->host;
+	long long *buf8 = (long long *)buf;
+	int i, j;
+
+	for (i = 0; i < host->ts_samples_count; i++) {
+		host->ts_samples[i].time = tep_read_number(handle->pevent,
+							   buf8 + i, 8);
+		host->ts_samples[i].offset = tep_read_number(handle->pevent,
+						buf8 + host->ts_samples_count+i, 8);
+	}
+	qsort(host->ts_samples, host->ts_samples_count,
+	      sizeof(struct ts_offset_sample), tsync_offset_cmp);
+	/* Filter possible samples with equal time */
+	for (i = 0, j = 0; i < host->ts_samples_count; i++) {
+		if (i == 0 || host->ts_samples[i].time != host->ts_samples[i-1].time)
+			host->ts_samples[j++] = host->ts_samples[i];
+	}
+	host->ts_samples_count = j;
+	if (j)
+		host->sync_enable = true;
+}
+
+static void trace_tsync_offset_free(struct host_trace_info *host)
+{
+	free(host->ts_samples);
+	host->ts_samples = NULL;
+}
+
 static int trace_pid_map_cmp(const void *a, const void *b)
 {
 	struct tracecmd_proc_addr_map *m_a = (struct tracecmd_proc_addr_map *)a;
@@ -2224,6 +2342,7 @@ static int handle_options(struct tracecmd_input *handle)
 	struct input_buffer_instance *buffer;
 	struct hook_list *hook;
 	char *buf;
+	int samples_size;
 	int cpus;
 
 	/* By default, use usecs, unless told otherwise */
@@ -2271,6 +2390,30 @@ static int handle_options(struct tracecmd_input *handle)
 			offset = strtoll(buf, NULL, 0);
 			handle->ts_offset += offset;
 			break;
+		case TRACECMD_OPTION_TIME_SHIFT:
+			/*
+			 * long long int (8 bytes) trace session ID
+			 * int (4 bytes) count of timestamp offsets.
+			 * long long array of size [count] of times,
+			 *      when the offsets were calculated.
+			 * long long array of size [count] of timestamp offsets.
+			 */
+			if (size < 12 || handle->flags & TRACECMD_FL_IGNORE_DATE)
+				break;
+			handle->host.trace_id = tep_read_number(handle->pevent,
+								buf, 8);
+			handle->host.ts_samples_count = tep_read_number(handle->pevent,
+									buf + 8, 4);
+			samples_size = (8 * handle->host.ts_samples_count);
+			if (size != (12 + (2 * samples_size))) {
+				warning("Failed to extract Time Shift information from the file, unexpected size %d", size);
+				break;
+			}
+			handle->host.ts_samples = malloc(2 * samples_size);
+			if (!handle->host.ts_samples)
+				return -ENOMEM;
+			tsync_offset_load(handle, buf + 12);
+			break;
 		case TRACECMD_OPTION_CPUSTAT:
 			buf[size-1] = '\n';
 			cpustats = realloc(cpustats, cpustats_size + size + 1);
@@ -2974,6 +3117,8 @@ void tracecmd_close(struct tracecmd_input *handle)
 	trace_pid_map_free(handle->pid_maps);
 	handle->pid_maps = NULL;
 
+	trace_tsync_offset_free(&handle->host);
+
 	if (handle->flags & TRACECMD_FL_BUFFER_INSTANCE)
 		tracecmd_close(handle->parent);
 	else {
@@ -3315,6 +3460,7 @@ tracecmd_buffer_instance_handle(struct tracecmd_input *handle, int indx)
 			return NULL;
 		}
 	}
+	memset(&new_handle->host, 0, sizeof(new_handle->host));
 	new_handle->parent = handle;
 	new_handle->cpustats = NULL;
 	new_handle->hooks = NULL;
@@ -3435,3 +3581,38 @@ unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle)
 {
 	return handle->trace_id;
 }
+
+/**
+ * tracecmd_get_tsync_peer - get the trace session id of the peer host
+ * @handle: input handle for the trace.dat file
+ *
+ * Returns the trace id of the peer host, written in the trace file
+ *
+ * This information is stored in guest trace.dat file
+ */
+unsigned long long tracecmd_get_tsync_peer(struct tracecmd_input *handle)
+{
+	return handle->host.trace_id;
+}
+
+/**
+ * tracecmd_enable_tsync - enable / disable the timestamps correction
+ * @handle: input handle for the trace.dat file
+ * @enable: enable / disable the timestamps correction
+ *
+ * Enables or disables timestamps correction on file load, using the array of
+ * recorded time offsets. If "enable" is true, but there are no time offsets,
+ * function fails and -1 is returned.
+ *
+ * Returns -1 in case of an error, or 0 otherwise
+ */
+int tracecmd_enable_tsync(struct tracecmd_input *handle, bool enable)
+{
+	if (enable &&
+	    (!handle->host.ts_samples || !handle->host.ts_samples_count))
+		return -1;
+
+	handle->host.sync_enable = enable;
+
+	return 0;
+}
diff --git a/tracecmd/trace-dump.c b/tracecmd/trace-dump.c
index 2dfeaa0f..b4beb8b2 100644
--- a/tracecmd/trace-dump.c
+++ b/tracecmd/trace-dump.c
@@ -366,6 +366,52 @@ static void dump_option_xlong(int fd, int size, char *desc)
 	read_file_number(fd, &val, size);
 	do_print(OPTIONS, "0x%llX\n", val);
 }
+
+static void dump_option_timeshift(int fd, int size)
+{
+	long long *offsets = NULL;
+	long long *times = NULL;
+	long long trace_id;
+	unsigned int count;
+	int i;
+
+	/*
+	 * long long int (8 bytes) trace session ID
+	 * int (4 bytes) count of timestamp offsets.
+	 * long long array of size [count] of times,
+	 *      when the offsets were calculated.
+	 * long long array of size [count] of timestamp offsets.
+	 */
+	if (size < 12) {
+		do_print(OPTIONS, "Broken time shift option, size %s", size);
+		return;
+	}
+	do_print(OPTIONS, "\t\t[Option TimeShift, %d bytes]\n", size);
+	read_file_number(fd, &trace_id, 8);
+	do_print(OPTIONS, "0x%llX [peer's trace id]\n", trace_id);
+	read_file_number(fd, &count, 4);
+	do_print(OPTIONS, "%lld [samples count]\n", count);
+	times = calloc(count, sizeof(long long));
+	if (!times)
+		goto out;
+	offsets = calloc(count, sizeof(long long));
+	if (!offsets)
+		goto out;
+
+	for (i = 0; i < count; i++)
+		read_file_number(fd, times + i, 8);
+	for (i = 0; i < count; i++)
+		read_file_number(fd, offsets + i, 8);
+
+	for (i = 0; i < count; i++)
+		do_print(OPTIONS, "\t%lld %lld [offset @ time]\n",
+			 offsets[i], times[i]);
+
+out:
+	free(times);
+	free(offsets);
+}
+
 static void dump_options(int fd)
 {
 	unsigned short option;
@@ -419,6 +465,9 @@ static void dump_options(int fd)
 		case TRACECMD_OPTION_TRACEID:
 			dump_option_xlong(fd, size, "TRACEID");
 			break;
+		case TRACECMD_OPTION_TIME_SHIFT:
+			dump_option_timeshift(fd, size);
+			break;
 		default:
 			do_print(OPTIONS, " %d %d\t[Unknown option, size - skipping]\n",
 				 option, size);
-- 
2.24.1

[PATCH v20 10/15] trace-cmd: Add guest information in host's trace.dat file

[Tzvetomir Stoyanov (VMware)]

New trace.dat option is introduced: TRACECMD_OPTION_GUEST.
Written in the host's trace.dat file, it contains information about
guests, traced at the same time: guest trace ID, number of VCPUs and
PIDs of the host tasks, running those VCPU. The data is stored in
the file as:
	Guest name, null terminated string
	long long (8 bytes) trace-id
	int (4 bytes) number of guest CPUs
	array of size number of guest CPUs:
		int (4 bytes) Guest CPU id
		int (4 bytes) Host PID, running the guest CPU

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/trace-cmd/trace-cmd.h |   5 ++
 lib/trace-cmd/trace-input.c   | 128 ++++++++++++++++++++++++++++++++++
 tracecmd/trace-dump.c         |  62 ++++++++++++++++
 tracecmd/trace-record.c       |  61 ++++++++++++++++
 4 files changed, 256 insertions(+)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index ac46637e..0375f500 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -111,6 +111,7 @@ enum {
 	TRACECMD_OPTION_PROCMAPS,
 	TRACECMD_OPTION_TRACEID,
 	TRACECMD_OPTION_TIME_SHIFT,
+	TRACECMD_OPTION_GUEST,
 };
 
 enum {
@@ -154,6 +155,10 @@ void tracecmd_set_flag(struct tracecmd_input *handle, int flag);
 void tracecmd_clear_flag(struct tracecmd_input *handle, int flag);
 unsigned long tracecmd_get_flags(struct tracecmd_input *handle);
 unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle);
+int tracecmd_get_guest_cpumap(struct tracecmd_input *handle,
+			      unsigned long long trace_id,
+			      char **name,
+			      int *vcpu_count, int **cpu_pid);
 unsigned long long tracecmd_get_tsync_peer(struct tracecmd_input *handle);
 int tracecmd_enable_tsync(struct tracecmd_input *handle, bool enable);
 
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index cf7be730..d13fff36 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -82,6 +82,14 @@ struct ts_offset_sample {
 	long long	offset;
 };
 
+struct guest_trace_info {
+	struct guest_trace_info	*next;
+	char			*name;
+	unsigned long long	trace_id;
+	int			vcpu_count;
+	int			*cpu_pid;
+};
+
 struct host_trace_info {
 	bool			sync_enable;
 	unsigned long long	trace_id;
@@ -115,6 +123,7 @@ struct tracecmd_input {
 	char *			trace_clock;
 	struct input_buffer_instance	*buffers;
 	int			parsing_failures;
+	struct guest_trace_info	*guest;
 
 	struct tracecmd_ftrace	finfo;
 
@@ -2197,6 +2206,86 @@ static void procmap_free(struct pid_addr_maps *maps)
 	free(maps);
 }
 
+static void trace_guests_free(struct tracecmd_input *handle)
+{
+	struct guest_trace_info *guest;
+
+	while (handle->guest) {
+		guest = handle->guest;
+		handle->guest = handle->guest->next;
+		free(guest->name);
+		free(guest->cpu_pid);
+		free(guest);
+	}
+}
+
+static int trace_guest_load(struct tracecmd_input *handle, char *buf, int size)
+{
+	struct guest_trace_info *guest = NULL;
+	int cpu;
+	int i;
+
+	guest = calloc(1, sizeof(struct guest_trace_info));
+	if (!guest)
+		goto error;
+
+	/*
+	 * Guest name, null terminated string
+	 * long long (8 bytes) trace-id
+	 * int (4 bytes) number of guest CPUs
+	 * array of size number of guest CPUs:
+	 *	int (4 bytes) Guest CPU id
+	 *	int (4 bytes) Host PID, running the guest CPU
+	 */
+
+	guest->name = strndup(buf, size);
+	if (!guest->name)
+		goto error;
+	buf += strlen(guest->name) + 1;
+	size -= strlen(guest->name) + 1;
+
+	if (size < sizeof(long long))
+		goto error;
+	guest->trace_id = tep_read_number(handle->pevent, buf, sizeof(long long));
+	buf += sizeof(long long);
+	size -= sizeof(long long);
+
+	if (size < sizeof(int))
+		goto error;
+	guest->vcpu_count = tep_read_number(handle->pevent, buf, sizeof(int));
+	buf += sizeof(int);
+	size -= sizeof(int);
+
+	guest->cpu_pid = calloc(guest->vcpu_count, sizeof(int));
+	if (!guest->cpu_pid)
+		goto error;
+
+	for (i = 0; i < guest->vcpu_count; i++) {
+		if (size < 2 * sizeof(int))
+			goto error;
+		cpu = tep_read_number(handle->pevent, buf, sizeof(int));
+		buf += sizeof(int);
+		if (cpu >= guest->vcpu_count)
+			goto error;
+		guest->cpu_pid[cpu] = tep_read_number(handle->pevent,
+						      buf, sizeof(int));
+		buf += sizeof(int);
+		size -= 2 * sizeof(int);
+	}
+
+	guest->next = handle->guest;
+	handle->guest = guest;
+	return 0;
+
+error:
+	if (guest) {
+		free(guest->cpu_pid);
+		free(guest->name);
+		free(guest);
+	}
+	return -1;
+}
+
 /* Needs to be a constant, and 4K should be good enough */
 #define STR_PROCMAP_LINE_MAX	4096
 static int trace_pid_map_load(struct tracecmd_input *handle, char *buf)
@@ -2464,6 +2553,9 @@ static int handle_options(struct tracecmd_input *handle)
 			handle->trace_id = tep_read_number(handle->pevent,
 							   &cpus, 8);
 			break;
+		case TRACECMD_OPTION_GUEST:
+			trace_guest_load(handle, buf, size);
+			break;
 		default:
 			warning("unknown option %d", option);
 			break;
@@ -3118,6 +3210,7 @@ void tracecmd_close(struct tracecmd_input *handle)
 	handle->pid_maps = NULL;
 
 	trace_tsync_offset_free(&handle->host);
+	trace_guests_free(handle);
 
 	if (handle->flags & TRACECMD_FL_BUFFER_INSTANCE)
 		tracecmd_close(handle->parent);
@@ -3582,6 +3675,41 @@ unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle)
 	return handle->trace_id;
 }
 
+/**
+ * tracecmd_get_guest_cpumap - get the mapping of guest VCPU to host process
+ * @handle: input handle for the trace.dat file
+ * @trace_id: ID of the guest tracing session
+ * @name: return, name of the guest
+ * @vcpu_count: return, number of VPUs
+ * @cpu_pid: return, array with guest VCPU to host process mapping
+ *
+ * Returns @name of the guest, number of VPUs (@vcpu_count)
+ * and array @cpu_pid with size @vcpu_count. Array index is VCPU id, array
+ * content is PID of the host process, running this VCPU.
+ *
+ * This information is stored in host trace.dat file
+ */
+int tracecmd_get_guest_cpumap(struct tracecmd_input *handle,
+			      unsigned long long trace_id,
+			      char **name,
+			      int *vcpu_count, int **cpu_pid)
+{
+	struct guest_trace_info	*guest = handle->guest;
+
+	while (guest) {
+		if (guest->trace_id == trace_id)
+			break;
+		guest = guest->next;
+	}
+	if (!guest)
+		return -1;
+
+	*name = guest->name;
+	*vcpu_count = guest->vcpu_count;
+	*cpu_pid = guest->cpu_pid;
+	return 0;
+}
+
 /**
  * tracecmd_get_tsync_peer - get the trace session id of the peer host
  * @handle: input handle for the trace.dat file
diff --git a/tracecmd/trace-dump.c b/tracecmd/trace-dump.c
index b4beb8b2..ffb1c6b1 100644
--- a/tracecmd/trace-dump.c
+++ b/tracecmd/trace-dump.c
@@ -412,6 +412,65 @@ out:
 	free(offsets);
 }
 
+void dump_option_guest(int fd, int size)
+{
+	unsigned long long trace_id;
+	char *buf, *p;
+	int cpu, pid;
+	int cpus;
+	int i;
+
+	do_print(OPTIONS, "\t\t[Option GUEST, %d bytes]\n", size);
+
+	/*
+	 * Guest name, null terminated string
+	 * long long (8 bytes) trace-id
+	 * int (4 bytes) number of guest CPUs
+	 * array of size number of guest CPUs:
+	 *	int (4 bytes) Guest CPU id
+	 *	int (4 bytes) Host PID, running the guest CPU
+	 */
+	buf = calloc(1, size);
+	if (!buf)
+		return;
+	if (read_file_bytes(fd, buf, size))
+		goto out;
+
+	p = buf;
+	do_print(OPTIONS, "%s [Guest name]\n", p);
+	size -= strlen(buf) + 1;
+	p += strlen(buf) + 1;
+
+	if (size < sizeof(long long))
+		goto out;
+	trace_id = tep_read_number(tep, p, sizeof(long long));
+	size -= sizeof(long long);
+	p += sizeof(long long);
+	do_print(OPTIONS, "0x%llX [trace id]\n", trace_id);
+
+	if (size < sizeof(int))
+		goto out;
+	cpus = tep_read_number(tep, p, sizeof(int));
+	size -= sizeof(int);
+	p += sizeof(int);
+	do_print(OPTIONS, "%d [Guest CPUs]\n", cpus);
+
+	for (i = 0; i < cpus; i++) {
+		if (size < 2 * sizeof(int))
+			goto out;
+		cpu = tep_read_number(tep, p, sizeof(int));
+		size -= sizeof(int);
+		p += sizeof(int);
+		pid = tep_read_number(tep, p, sizeof(int));
+		size -= sizeof(int);
+		p += sizeof(int);
+		do_print(OPTIONS, "  %d %d [guest cpu, host pid]\n", cpu, pid);
+	}
+
+out:
+	free(buf);
+}
+
 static void dump_options(int fd)
 {
 	unsigned short option;
@@ -468,6 +527,9 @@ static void dump_options(int fd)
 		case TRACECMD_OPTION_TIME_SHIFT:
 			dump_option_timeshift(fd, size);
 			break;
+		case TRACECMD_OPTION_GUEST:
+			dump_option_guest(fd, size);
+			break;
 		default:
 			do_print(OPTIONS, " %d %d\t[Unknown option, size - skipping]\n",
 				 option, size);
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 7427fea4..5f799908 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -3059,6 +3059,19 @@ static int set_vcpu_pid_mapping(struct guest *guest, int cpu, int pid)
 	return 0;
 }
 
+static struct guest *get_guest_info(unsigned int guest_cid)
+{
+	int i;
+
+	if (!guests)
+		return NULL;
+
+	for (i = 0; i < guests_len; i++)
+		if (guest_cid == guests[i].cid)
+			return guests + i;
+	return NULL;
+}
+
 static char *get_qemu_guest_name(char *arg)
 {
 	char *tok, *end = arg;
@@ -3867,6 +3880,49 @@ static void append_buffer(struct tracecmd_output *handle,
 	}
 }
 
+static void
+add_guest_info(struct tracecmd_output *handle, struct buffer_instance *instance)
+{
+	struct guest *guest = get_guest_info(instance->cid);
+	char *buf, *p;
+	int size;
+	int i;
+
+	if (!guest)
+		return;
+	for (i = 0; i < guest->cpu_max; i++)
+		if (!guest->cpu_pid[i])
+			break;
+
+	size = strlen(guest->name) + 1;
+	size +=  sizeof(long long); 	/* trace_id */
+	size +=  sizeof(int);		/* cpu count */
+	size += i * 2 * sizeof(int);	/* cpu,pid pair */
+
+	buf = calloc(1, size);
+	if (!buf)
+		return;
+	p = buf;
+	strcpy(p, guest->name);
+	p += strlen(guest->name) + 1;
+
+	memcpy(p, &instance->trace_id, sizeof(long long));
+	p += sizeof(long long);
+
+	memcpy(p, &i, sizeof(int));
+	p += sizeof(int);
+	for (i = 0; i < guest->cpu_max; i++) {
+		if (!guest->cpu_pid[i])
+			break;
+		memcpy(p, &i, sizeof(int));
+		p += sizeof(int);
+		memcpy(p, &guest->cpu_pid[i], sizeof(int));
+		p += sizeof(int);
+	}
+
+	tracecmd_add_option(handle, TRACECMD_OPTION_GUEST, size, buf);
+	free(buf);
+}
 
 static void
 add_pid_maps(struct tracecmd_output *handle, struct buffer_instance *instance)
@@ -4151,6 +4207,11 @@ static void record_data(struct common_record_context *ctx)
 			add_pid_maps(handle, instance);
 		}
 
+		for_all_instances(instance) {
+			if (is_guest(instance))
+				add_guest_info(handle, instance);
+		}
+
 		tracecmd_append_cpu_data(handle, local_cpu_count, temp_files);
 
 		for (i = 0; i < max_cpu_count; i++)
-- 
2.24.1

[PATCH v20 11/15] trace-cmd: Add host trace clock as guest trace argument

[Tzvetomir Stoyanov (VMware)]

When tracing host and guest machines, both should use the same
tracing clock for event timestamps. If a clock is specified
as host tracing argument, with option "-C clock_name", the same
is injected as guest tracing argument. If the user wants to use
different tracing clocks, it can specify it using "-C clock_name"
as guest tracing argument. In that case, the one specified by
the user has higher priority.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 tracecmd/include/trace-local.h |  1 +
 tracecmd/trace-record.c        | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index 4f2b5541..dc934f28 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -167,6 +167,7 @@ enum buffer_instance_flags {
 	BUFFER_FL_PROFILE	= 1 << 1,
 	BUFFER_FL_GUEST		= 1 << 2,
 	BUFFER_FL_AGENT		= 1 << 3,
+	BUFFER_FL_HAS_CLOCK	= 1 << 4,
 };
 
 struct func_list {
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 5f799908..ee27cf0f 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -5555,6 +5555,8 @@ static void parse_record_options(int argc,
 	char *sav;
 	int name_counter = 0;
 	int neg_event = 0;
+	struct buffer_instance *instance;
+	bool guest_sync_set = false;
 
 	init_common_record_context(ctx, curr_cmd);
 
@@ -5598,6 +5600,8 @@ static void parse_record_options(int argc,
 		 */
 		if (c != 'B' && c != 'A' && is_guest(ctx->instance)) {
 			add_arg(ctx->instance, c, opts, long_options, optarg);
+			if (c == 'C')
+				ctx->instance->flags |= BUFFER_FL_HAS_CLOCK;
 			continue;
 		}
 
@@ -5712,6 +5716,9 @@ static void parse_record_options(int argc,
 			break;
 		case 'C':
 			ctx->instance->clock = optarg;
+			ctx->instance->flags |= BUFFER_FL_HAS_CLOCK;
+			if (is_top_instance(ctx->instance))
+				guest_sync_set = true;
 			break;
 		case 'v':
 			neg_event = 1;
@@ -5936,6 +5943,20 @@ static void parse_record_options(int argc,
 				add_argv(instance, "--date", true);
 		}
 	}
+	if (guest_sync_set) {
+	/* If -C is specified, prepend clock to all guest VM flags */
+		for_all_instances(instance) {
+			if (top_instance.clock) {
+				if (is_guest(instance) &&
+				    !(instance->flags & BUFFER_FL_HAS_CLOCK)) {
+					add_argv(instance,
+						 (char *)top_instance.clock,
+						 true);
+					add_argv(instance, "-C", true);
+				}
+			}
+		}
+	}
 
 	if (!ctx->filtered && ctx->instance->filter_mod)
 		add_func(&ctx->instance->filter_funcs,
-- 
2.24.1

[PATCH v20 12/15] trace-cmd: Refactor few trace-cmd internal functions.

[Tzvetomir Stoyanov (VMware)]

In order to reuse code inside trace-cmd application context,
few functions are made non static and "trace_" is prepended
to their names:
	int trace_make_vsock(unsigned int port);
	int trace_get_vsock_port(int sd, unsigned int *port);
	int trace_open_vsock(unsigned int cid, unsigned int port);
	char *trace_get_guest_file(const char *file, const char *guest);

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 tracecmd/include/trace-local.h |  6 ++++++
 tracecmd/trace-agent.c         | 10 +++++-----
 tracecmd/trace-record.c        | 18 +++++++++---------
 3 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index dc934f28..95d0026b 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -263,6 +263,12 @@ void tracecmd_disable_tracing(void);
 void tracecmd_enable_tracing(void);
 void tracecmd_stat_cpu(struct trace_seq *s, int cpu);
 
+int trace_make_vsock(unsigned int port);
+int trace_get_vsock_port(int sd, unsigned int *port);
+int trace_open_vsock(unsigned int cid, unsigned int port);
+
+char *trace_get_guest_file(const char *file, const char *guest);
+
 /* No longer in event-utils.h */
 void __noreturn die(const char *fmt, ...); /* Can be overriden */
 void *malloc_or_die(unsigned int size); /* Can be overridden */
diff --git a/tracecmd/trace-agent.c b/tracecmd/trace-agent.c
index 52d27195..a8ef0852 100644
--- a/tracecmd/trace-agent.c
+++ b/tracecmd/trace-agent.c
@@ -40,7 +40,7 @@ static int get_local_cid(unsigned int *cid)
 	return ret;
 }
 
-static int make_vsock(unsigned int port)
+int trace_make_vsock(unsigned int port)
 {
 	struct sockaddr_vm addr = {
 		.svm_family = AF_VSOCK,
@@ -64,7 +64,7 @@ static int make_vsock(unsigned int port)
 	return sd;
 }
 
-static int get_vsock_port(int sd, unsigned int *port)
+int trace_get_vsock_port(int sd, unsigned int *port)
 {
 	struct sockaddr_vm addr;
 	socklen_t addr_len = sizeof(addr);
@@ -87,11 +87,11 @@ static void make_vsocks(int nr, int *fds, unsigned int *ports)
 	int i, fd, ret;
 
 	for (i = 0; i < nr; i++) {
-		fd = make_vsock(VMADDR_PORT_ANY);
+		fd = trace_make_vsock(VMADDR_PORT_ANY);
 		if (fd < 0)
 			die("Failed to open vsocket");
 
-		ret = get_vsock_port(fd, &port);
+		ret = trace_get_vsock_port(fd, &port);
 		if (ret < 0)
 			die("Failed to get vsocket address");
 
@@ -210,7 +210,7 @@ static void agent_serve(unsigned int port)
 	nr_cpus = tracecmd_count_cpus();
 	page_size = getpagesize();
 
-	sd = make_vsock(port);
+	sd = trace_make_vsock(port);
 	if (sd < 0)
 		die("Failed to open vsocket");
 
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index ee27cf0f..30ba5bb2 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -537,7 +537,7 @@ static char *get_temp_file(struct buffer_instance *instance, int cpu)
 	return file;
 }
 
-static char *get_guest_file(const char *file, const char *guest)
+char *trace_get_guest_file(const char *file, const char *guest)
 {
 	const char *p;
 	char *out = NULL;
@@ -2930,7 +2930,7 @@ static int connect_port(const char *host, unsigned int port)
 }
 
 #ifdef VSOCK
-static int open_vsock(unsigned int cid, unsigned int port)
+int trace_open_vsock(unsigned int cid, unsigned int port)
 {
 	struct sockaddr_vm addr = {
 		.svm_family = AF_VSOCK,
@@ -2993,7 +2993,7 @@ static bool can_splice_read_vsock(void)
 }
 
 #else
-static inline int open_vsock(unsigned int cid, unsigned int port)
+int trace_open_vsock(unsigned int cid, unsigned int port)
 {
 	die("vsock is not supported");
 	return -1;
@@ -3297,7 +3297,7 @@ create_recorder_instance(struct buffer_instance *instance, const char *file, int
 		if (instance->use_fifos)
 			fd = instance->fds[cpu];
 		else
-			fd = open_vsock(instance->cid, instance->client_ports[cpu]);
+			fd = trace_open_vsock(instance->cid, instance->client_ports[cpu]);
 		if (fd < 0)
 			die("Failed to connect to agent");
 
@@ -3689,7 +3689,7 @@ static void connect_to_agent(struct buffer_instance *instance)
 		use_fifos = nr_fifos > 0;
 	}
 
-	sd = open_vsock(instance->cid, instance->port);
+	sd = trace_open_vsock(instance->cid, instance->port);
 	if (sd < 0)
 		die("Failed to connect to vsocket @%u:%u",
 		    instance->cid, instance->port);
@@ -3740,8 +3740,8 @@ static void setup_guest(struct buffer_instance *instance)
 	int fd;
 
 	/* Create a place to store the guest meta data */
-	file = get_guest_file(output_file,
-			      tracefs_instance_get_name(instance->tracefs));
+	file = trace_get_guest_file(output_file,
+				    tracefs_instance_get_name(instance->tracefs));
 	if (!file)
 		die("Failed to allocate memory");
 
@@ -4077,8 +4077,8 @@ static void write_guest_file(struct buffer_instance *instance)
 	char **temp_files;
 	int i, fd;
 
-	file = get_guest_file(output_file,
-			      tracefs_instance_get_name(instance->tracefs));
+	file = trace_get_guest_file(output_file,
+				    tracefs_instance_get_name(instance->tracefs));
 	if (!file)
 		die("Failed to allocate memory");
 
-- 
2.24.1

[PATCH v20 13/15] trace-cmd: Basic infrastructure for host - guest timestamp synchronization

[Tzvetomir Stoyanov (VMware)]

The infrastructure for host - guest timestamp synchronization is divided
in two parts:
 - logic in libtracecmd
 - logic in trace-cmd application

The libtracecmd is extended with new trace message, MSG_TIME_SYNC, used to
exchange time synch information between host and guest. The trace request and
response messages are extended to handle the time synch negotiation. The logic
is implemented in trace-timesync.c file:
 - Register / unregister time sync protocols.
 - Choosing what protocol will be used for a tracing session.
 - Init common context, used by all protocols - a ftrace instance, vsockets.
 - Invoke protocol routines to perform time synchronization.
 - Store calculated offsets in an array.

The trace-cmd application is extended to perform timestamp synchronization.
The main logic is in trace-tsync.c file
 - Negotiate what time synch algorithm will be used for the tracing session.
 - Run pthreads, to do continuous timestamp synchronization, during the trace.
 - Store calculated offsets in guest's trace.dat file, using TRACECMD_OPTION_TIME_SHIFT option
 - A new trace-cmd option is added, to control the timestamp synchronization:
      --tsync-interval: set the time sync loop interval, in ms. The default
   value is 0 - timestamp synchronization is performed twice, before and after
   the trace. If a negative number is specified, the timestamp synchronization
   is disabled.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/trace-cmd-record.1.txt      |   7 +
 include/trace-cmd/trace-cmd.h             |  58 ++-
 lib/trace-cmd/Makefile                    |   1 +
 lib/trace-cmd/include/trace-tsync-local.h |  38 ++
 lib/trace-cmd/trace-msg.c                 | 395 ++++++++++++++---
 lib/trace-cmd/trace-timesync.c            | 498 ++++++++++++++++++++++
 tracecmd/Makefile                         |   3 +-
 tracecmd/include/trace-local.h            |  11 +
 tracecmd/trace-agent.c                    |  39 +-
 tracecmd/trace-record.c                   |  40 +-
 tracecmd/trace-tsync.c                    | 272 ++++++++++++
 tracecmd/trace-usage.c                    |   4 +
 12 files changed, 1299 insertions(+), 67 deletions(-)
 create mode 100644 lib/trace-cmd/include/trace-tsync-local.h
 create mode 100644 lib/trace-cmd/trace-timesync.c
 create mode 100644 tracecmd/trace-tsync.c

diff --git a/Documentation/trace-cmd-record.1.txt b/Documentation/trace-cmd-record.1.txt
index 0d75e43d..f5ecad5c 100644
--- a/Documentation/trace-cmd-record.1.txt
+++ b/Documentation/trace-cmd-record.1.txt
@@ -338,6 +338,13 @@ OPTIONS
     the offset will also be in nanoseconds even if the displayed units are
     in microseconds.
 
+*--tsync-interval*::
+    Set the loop interval, in ms, for timestamps synchronization with guests:
+        If a negative number is specified, timestamps synchronization is disabled
+        If 0 is specified, no loop is performed - timestamps offset is calculated only twice,"
+        at the beginning and at the end of the trace.
+        Timestamps synchronization with guests works only if there is support for VSOCK.\n"
+
 *--stderr*::
     Have output go to stderr instead of stdout, but the output of the command
     executed will not be changed. This is useful if you want to monitor the
diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 0375f500..42b47e2f 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -379,19 +379,69 @@ void tracecmd_msg_set_done(struct tracecmd_msg_handle *msg_handle);
 
 int tracecmd_msg_send_trace_req(struct tracecmd_msg_handle *msg_handle,
 				int argc, char **argv, bool use_fifos,
-				unsigned long long trace_id);
+				unsigned long long trace_id,
+				char *tsync_protos,
+				int tsync_protos_size);
 int tracecmd_msg_recv_trace_req(struct tracecmd_msg_handle *msg_handle,
 				int *argc, char ***argv, bool *use_fifos,
-				unsigned long long *trace_id);
+				unsigned long long *trace_id,
+				char **tsync_protos,
+				unsigned int *tsync_protos_size);
 
 int tracecmd_msg_send_trace_resp(struct tracecmd_msg_handle *msg_handle,
 				 int nr_cpus, int page_size,
 				 unsigned int *ports, bool use_fifos,
-				 unsigned long long trace_id);
+				 unsigned long long trace_id,
+				 unsigned int tsync_proto,
+				 unsigned int tsync_port);
 int tracecmd_msg_recv_trace_resp(struct tracecmd_msg_handle *msg_handle,
 				 int *nr_cpus, int *page_size,
 				 unsigned int **ports, bool *use_fifos,
-				 unsigned long long *trace_id);
+				 unsigned long long *trace_id,
+				 unsigned int *tsync_proto,
+				 unsigned int *tsync_port);
+
+int tracecmd_msg_send_time_sync(struct tracecmd_msg_handle *msg_handle,
+				unsigned int sync_protocol,
+				unsigned int sync_msg_id,
+				unsigned int payload_size, char *payload);
+int tracecmd_msg_recv_time_sync(struct tracecmd_msg_handle *msg_handle,
+				unsigned int *sync_protocol,
+				unsigned int *sync_msg_id,
+				unsigned int *payload_size, char **payload);
+
+/* --- Timestamp synchronization --- */
+
+enum{
+	TRACECMD_TIME_SYNC_PROTO_NONE	= 0,
+};
+enum{
+	TRACECMD_TIME_SYNC_CMD_PROBE	= 1,
+	TRACECMD_TIME_SYNC_CMD_STOP	= 2,
+};
+
+#define TRACECMD_TIME_SYNC_PROTO_PTP_WEIGHT	10
+
+struct tracecmd_time_sync {
+	unsigned int			sync_proto;
+	int				loop_interval;
+	pthread_mutex_t			lock;
+	pthread_cond_t			cond;
+	char				*clock_str;
+	struct tracecmd_msg_handle	*msg_handle;
+	void				*context;
+};
+
+void tracecmd_tsync_init(void);
+int tracecmd_tsync_proto_getall(char **proto_mask, int *words);
+unsigned int tracecmd_tsync_proto_select(char *proto_mask, int words);
+bool tsync_proto_is_supported(unsigned int proto_id);
+void tracecmd_tsync_with_host(struct tracecmd_time_sync *tsync);
+void tracecmd_tsync_with_guest(struct tracecmd_time_sync *tsync);
+int tracecmd_tsync_get_offsets(struct tracecmd_time_sync *tsync,
+				int *count,
+				long long **ts, long long **offsets);
+void tracecmd_tsync_free(struct tracecmd_time_sync *tsync);
 
 /* --- Plugin handling --- */
 extern struct tep_plugin_option trace_ftrace_options[];
diff --git a/lib/trace-cmd/Makefile b/lib/trace-cmd/Makefile
index 29c36ca1..ab7440ac 100644
--- a/lib/trace-cmd/Makefile
+++ b/lib/trace-cmd/Makefile
@@ -16,6 +16,7 @@ OBJS += trace-util.o
 OBJS += trace-filter-hash.o
 OBJS += trace-msg.o
 OBJS += trace-plugin.o
+OBJS += trace-timesync.o
 
 # Additional util objects
 OBJS += trace-blk-hack.o
diff --git a/lib/trace-cmd/include/trace-tsync-local.h b/lib/trace-cmd/include/trace-tsync-local.h
new file mode 100644
index 00000000..1de9d5e5
--- /dev/null
+++ b/lib/trace-cmd/include/trace-tsync-local.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: LGPL-2.1 */
+/*
+ * Copyright (C) 2019, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
+ *
+ */
+#ifndef _TRACE_TSYNC_LOCAL_H
+#define _TRACE_TSYNC_LOCAL_H
+
+#include <stdbool.h>
+
+struct clock_sync_context {
+	void				*proto_data;	/* time sync protocol specific data */
+	bool				is_server;	/* server side time sync role */
+	struct tracefs_instance		*instance;	/* ftrace buffer, used for time sync events */
+
+	/* Arrays with calculated time offsets at given time */
+	int				sync_size;	/* Allocated size of sync_ts and sync_offsets */
+	int				sync_count;	/* Number of elements in sync_ts and sync_offsets */
+	long long			*sync_ts;
+	long long			*sync_offsets;
+
+	/* Identifiers of local and remote time sync peers: cid and port */
+	unsigned int			local_cid;
+	unsigned int			local_port;
+	unsigned int			remote_cid;
+	unsigned int			remote_port;
+};
+
+int tracecmd_tsync_proto_register(unsigned int proto_id, int weight,
+				int (*init)(struct tracecmd_time_sync *),
+				int (*free)(struct tracecmd_time_sync *),
+				int (*calc)(struct tracecmd_time_sync *,
+					    long long *, long long *));
+int tracecmd_tsync_proto_unregister(unsigned int proto_id);
+
+int ptp_clock_sync_register(void);
+
+#endif /* _TRACE_TSYNC_LOCAL_H */
diff --git a/lib/trace-cmd/trace-msg.c b/lib/trace-cmd/trace-msg.c
index d6a68ac3..5a00dbf2 100644
--- a/lib/trace-cmd/trace-msg.c
+++ b/lib/trace-cmd/trace-msg.c
@@ -29,6 +29,8 @@
 
 typedef __u32 u32;
 typedef __be32 be32;
+typedef __u64 u64;
+typedef __s64 s64;
 
 static inline void dprint(const char *fmt, ...)
 {
@@ -61,6 +63,18 @@ struct tracecmd_msg_rinit {
 	be32 cpus;
 } __attribute__((packed));
 
+#define TRACE_REQ_PARAM_SIZE  (2 * sizeof(int))
+enum trace_req_params {
+	TRACE_REQUEST_ARGS,
+	TRACE_REQUEST_TSYNC_PROTOS,
+};
+
+struct tracecmd_msg_trace_req_param {
+	int id;
+	int length;
+	char *value;
+};
+
 struct tracecmd_msg_trace_req {
 	be32 flags;
 	be32 argc;
@@ -72,6 +86,13 @@ struct tracecmd_msg_trace_resp {
 	be32 cpus;
 	be32 page_size;
 	u64 trace_id;
+	be32 tsync_proto;
+	be32 tsync_port;
+} __attribute__((packed));
+
+struct tracecmd_msg_tsync {
+	be32 sync_protocol;
+	be32 sync_msg_id;
 } __attribute__((packed));
 
 struct tracecmd_msg_header {
@@ -89,7 +110,8 @@ struct tracecmd_msg_header {
 	C(NOT_SUPP,	5,	0),					\
 	C(TRACE_REQ,	6,	sizeof(struct tracecmd_msg_trace_req)),	\
 	C(TRACE_RESP,	7,	sizeof(struct tracecmd_msg_trace_resp)),\
-	C(CLOSE_RESP,	8,	0),
+	C(CLOSE_RESP,	8,	0),					\
+	C(TIME_SYNC,	9,	sizeof(struct tracecmd_msg_tsync)),
 
 #undef C
 #define C(a,b,c)	MSG_##a = b
@@ -123,6 +145,7 @@ struct tracecmd_msg {
 		struct tracecmd_msg_rinit	rinit;
 		struct tracecmd_msg_trace_req	trace_req;
 		struct tracecmd_msg_trace_resp	trace_resp;
+		struct tracecmd_msg_tsync	tsync;
 	};
 	char					*buf;
 } __attribute__((packed));
@@ -265,6 +288,17 @@ static int tracecmd_msg_send(int fd, struct tracecmd_msg *msg)
 	return ret;
 }
 
+static int msg_send_nofree(int fd, struct tracecmd_msg *msg)
+{
+	int ret = 0;
+
+	ret = msg_write(fd, msg);
+	if (ret < 0)
+		ret = -ECOMM;
+
+	return ret;
+}
+
 static int msg_read(int fd, void *buf, u32 size, int *n)
 {
 	ssize_t r;
@@ -814,81 +848,141 @@ int tracecmd_msg_wait_close_resp(struct tracecmd_msg_handle *msg_handle)
 	return tracecmd_msg_wait_for_cmd(msg_handle, MSG_CLOSE_RESP);
 }
 
-static int make_trace_req(struct tracecmd_msg *msg, int argc, char **argv,
-			  bool use_fifos, unsigned long long trace_id)
+static int make_trace_req_protos(char **buf, int *size,
+				 int protos_size, char *tsync_protos)
 {
-	size_t args_size = 0;
+	size_t buf_size;
+	char *nbuf;
+	char *p;
+
+	buf_size = TRACE_REQ_PARAM_SIZE + protos_size;
+	nbuf = realloc(*buf, *size + buf_size);
+	if (!nbuf)
+		return -1;
+
+	p = nbuf + *size;
+	memset(p, 0, buf_size);
+
+	*(unsigned int *)p = htonl(TRACE_REQUEST_TSYNC_PROTOS);
+	p += sizeof(int);
+	*(unsigned int *)p = htonl(protos_size);
+	p += sizeof(int);
+
+	memcpy(p, tsync_protos, protos_size);
+
+	*size += buf_size;
+	*buf = nbuf;
+	return 0;
+}
+
+static int make_trace_req_args(char **buf, int *size, int argc, char **argv)
+{
+	size_t args_size;
+	size_t buf_size;
+	char *nbuf;
 	char *p;
 	int i;
 
+	args_size = sizeof(int);
 	for (i = 0; i < argc; i++)
 		args_size += strlen(argv[i]) + 1;
 
-	msg->hdr.size = htonl(ntohl(msg->hdr.size) + args_size);
-	msg->trace_req.flags = use_fifos ? htonl(MSG_TRACE_USE_FIFOS) : htonl(0);
-	msg->trace_req.argc = htonl(argc);
-	msg->trace_req.trace_id = htonll(trace_id);
-	msg->buf = calloc(args_size, 1);
-	if (!msg->buf)
-		return -ENOMEM;
+	buf_size = TRACE_REQ_PARAM_SIZE + args_size;
+	nbuf = realloc(*buf, *size + buf_size);
+	if (!nbuf)
+		return -1;
+
+	p = nbuf + *size;
+	memset(p, 0, buf_size);
+
+	*(unsigned int *)p = htonl(TRACE_REQUEST_ARGS);
+	p += sizeof(int);
+	*(unsigned int *)p = htonl(args_size);
+	p += sizeof(int);
 
-	p = msg->buf;
+	*(unsigned int *)p = htonl(argc);
+	p += sizeof(int);
 	for (i = 0; i < argc; i++)
 		p = stpcpy(p, argv[i]) + 1;
 
+	*size += buf_size;
+	*buf = nbuf;
+	return 0;
+}
+
+static int make_trace_req(struct tracecmd_msg *msg, int argc, char **argv,
+			  bool use_fifos, unsigned long long trace_id,
+			  char *tsync_protos, int tsync_protos_size)
+{
+	int size = 0;
+	char *buf = NULL;
+
+	msg->trace_req.flags = 0;
+	if (use_fifos)
+		msg->trace_req.flags |= MSG_TRACE_USE_FIFOS;
+	msg->trace_req.flags = htonl(msg->trace_req.flags);
+	msg->trace_req.trace_id = htonll(trace_id);
+
+	if (argc && argv)
+		make_trace_req_args(&buf, &size, argc, argv);
+	if (tsync_protos_size && tsync_protos)
+		make_trace_req_protos(&buf, &size,
+				      tsync_protos_size, tsync_protos);
+
+	msg->buf = buf;
+	msg->hdr.size = htonl(ntohl(msg->hdr.size) + size);
+
 	return 0;
 }
 
 int tracecmd_msg_send_trace_req(struct tracecmd_msg_handle *msg_handle,
 				int argc, char **argv, bool use_fifos,
-				unsigned long long trace_id)
+				unsigned long long trace_id,
+				char *tsync_protos,
+				int tsync_protos_size)
 {
 	struct tracecmd_msg msg;
 	int ret;
 
 	tracecmd_msg_init(MSG_TRACE_REQ, &msg);
-	ret = make_trace_req(&msg, argc, argv, use_fifos, trace_id);
+	ret = make_trace_req(&msg, argc, argv, use_fifos,
+			     trace_id, tsync_protos, tsync_protos_size);
 	if (ret < 0)
 		return ret;
 
 	return tracecmd_msg_send(msg_handle->fd, &msg);
 }
 
- /*
-  * NOTE: On success, the returned `argv` should be freed with:
-  *     free(argv[0]);
-  *     free(argv);
-  */
-int tracecmd_msg_recv_trace_req(struct tracecmd_msg_handle *msg_handle,
-				int *argc, char ***argv, bool *use_fifos,
-				unsigned long long *trace_id)
+static int get_trace_req_protos(char *buf, int length,
+				char **tsync_protos,
+				unsigned int *tsync_protos_size)
 {
-	struct tracecmd_msg msg;
-	char *p, *buf_end, **args;
-	int i, ret, nr_args;
-	ssize_t buf_len;
+	*tsync_protos = malloc(length);
+	if (!*tsync_protos)
+		return -1;
+	memcpy(*tsync_protos, buf, length);
+	*tsync_protos_size = length;
 
-	ret = tracecmd_msg_recv(msg_handle->fd, &msg);
-	if (ret < 0)
-		return ret;
+	return 0;
+}
 
-	if (ntohl(msg.hdr.cmd) != MSG_TRACE_REQ) {
-		ret = -ENOTSUP;
-		goto out;
-	}
+static int get_trace_req_args(char *buf, int length, int *argc, char ***argv)
+{
+	unsigned int nr_args;
+	char *p, *buf_end;
+	char **args = NULL;
+	char *vagrs = NULL;
+	int ret;
+	int i;
 
-	nr_args = ntohl(msg.trace_req.argc);
-	if (nr_args <= 0) {
+	if (length <= sizeof(int) || buf[length - 1] != '\0') {
 		ret = -EINVAL;
 		goto out;
 	}
 
-	buf_len = ntohl(msg.hdr.size) - MSG_HDR_LEN - ntohl(msg.hdr.cmd_size);
-	buf_end = (char *)msg.buf + buf_len;
-	if (buf_len <= 0 && ((char *)msg.buf)[buf_len-1] != '\0') {
-		ret = -EINVAL;
-		goto out;
-	}
+	nr_args = ntohl(*(unsigned int *)buf);
+	buf += sizeof(int);
+	length -= sizeof(int);
 
 	args = calloc(nr_args, sizeof(*args));
 	if (!args) {
@@ -896,10 +990,18 @@ int tracecmd_msg_recv_trace_req(struct tracecmd_msg_handle *msg_handle,
 		goto out;
 	}
 
-	for (i = 0, p = msg.buf; i < nr_args; i++, p++) {
+	vagrs = calloc(length, sizeof(char));
+	if (!vagrs) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	memcpy(vagrs, buf, length);
+	buf_end = vagrs + length;
+	for (i = 0, p = vagrs; i < nr_args; i++, p++) {
 		if (p >= buf_end) {
 			ret = -EINVAL;
-			goto out_args;
+			goto out;
 		}
 		args[i] = p;
 		p = strchr(p, '\0');
@@ -907,18 +1009,82 @@ int tracecmd_msg_recv_trace_req(struct tracecmd_msg_handle *msg_handle,
 
 	*argc = nr_args;
 	*argv = args;
+	return 0;
+
+out:
+	free(args);
+	free(vagrs);
+	return ret;
+
+}
+
+/*
+ * NOTE: On success, the returned `argv` should be freed with:
+ *     free(argv[0]);
+ *     free(argv);
+ * and `tsync_protos` with free(tsync_protos);
+ */
+int tracecmd_msg_recv_trace_req(struct tracecmd_msg_handle *msg_handle,
+				int *argc, char ***argv, bool *use_fifos,
+				unsigned long long *trace_id,
+				char **tsync_protos,
+				unsigned int *tsync_protos_size)
+{
+	struct tracecmd_msg msg;
+	unsigned int param_id;
+	int param_length;
+	ssize_t buf_len;
+	char *p;
+	int ret;
+
+	ret = tracecmd_msg_recv(msg_handle->fd, &msg);
+	if (ret < 0)
+		return ret;
+
+	if (ntohl(msg.hdr.cmd) != MSG_TRACE_REQ) {
+		ret = -ENOTSUP;
+		goto out;
+	}
+
+	buf_len = ntohl(msg.hdr.size) - MSG_HDR_LEN - ntohl(msg.hdr.cmd_size);
+	if (buf_len < 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	*use_fifos = ntohl(msg.trace_req.flags) & MSG_TRACE_USE_FIFOS;
 	*trace_id = ntohll(msg.trace_req.trace_id);
-	/*
-	 * On success we're passing msg.buf to the caller through argv[0] so we
-	 * reset it here before calling msg_free().
-	 */
-	msg.buf = NULL;
+	p = msg.buf;
+	while (buf_len > 2 * sizeof(int)) {
+		param_id = ntohl(*((unsigned int *)p));
+		p += sizeof(int);
+		buf_len -= sizeof(int);
+		param_length = ntohl(*((unsigned int *)p));
+		p += sizeof(int);
+		buf_len -= sizeof(int);
+		if (buf_len < param_length)
+			break;
+		ret = 0;
+		switch (param_id) {
+		case TRACE_REQUEST_ARGS:
+			ret = get_trace_req_args(p, param_length, argc, argv);
+			break;
+		case TRACE_REQUEST_TSYNC_PROTOS:
+			ret = get_trace_req_protos(p, param_length,
+						   tsync_protos, tsync_protos_size);
+			break;
+		default:
+			break;
+		}
+		if (ret)
+			break;
+		buf_len -= param_length;
+		p += param_length;
+	}
+
 	msg_free(&msg);
 	return 0;
 
-out_args:
-	free(args);
 out:
 	error_operation(&msg);
 	if (ret == -EOPNOTSUPP)
@@ -927,9 +1093,118 @@ out:
 	return ret;
 }
 
+/**
+ * tracecmd_msg_send_time_sync - Send a time sync packet
+ * @msg_handle: message handle, holding the communication context
+ * @sync_protocol: id of the time synch protocol
+ * @sync_msg_id: id if the time synch message, protocol dependent
+ * @payload_size: size of the packet payload, 0 in case of no payload
+ * @payload: pointer to the packet payload, or NULL in case of no payload
+ *
+ * Returns 0 if packet is sent successfully, or negative error otherwise.
+ */
+int tracecmd_msg_send_time_sync(struct tracecmd_msg_handle *msg_handle,
+				unsigned int sync_protocol,
+				unsigned int sync_msg_id,
+				unsigned int payload_size, char *payload)
+{
+	struct tracecmd_msg msg;
+
+	tracecmd_msg_init(MSG_TIME_SYNC, &msg);
+	msg.tsync.sync_protocol = htonl(sync_protocol);
+	msg.tsync.sync_msg_id = htonl(sync_msg_id);
+	msg.hdr.size = htonl(ntohl(msg.hdr.size) + payload_size);
+
+	msg.buf = payload;
+	return msg_send_nofree(msg_handle->fd, &msg);
+}
+
+/**
+ * tracecmd_msg_recv_time_sync - Receive a time sync packet
+ * @msg_handle: message handle, holding the communication context
+ * @sync_protocol: return the id of the packet's time synch protocol
+ * @sync_msg_id: return the id of the packet's time synch message
+ * @payload_size: size of the packet's payload, can be:
+ *		 NULL - the payload is not interested and should be ignored
+ *		 pointer to int, with value 0 - update with the size of the payload
+ *						allocate memory and cpy the payload
+ *						into it
+ *		 pointer to int, with value greater than 0 - expected size of the
+ *							     payload, preallocated
+ *							     memory is passed to the API
+ *							     with that size
+ *@payload: pointer to the packet payload, can be:
+ *	     NULL - the payload is not interested and should be ignored
+ *	     pointer to char *, with value NULL - a new memory is allocated and returned
+ *						  here, containing the packet's payload
+ *						  the @payload_size is updated with the
+ *						  size of the allocated memory. It must be
+ *						  freed by free()
+ *	     pointer to char *, with no-NULL value - A prealocated array is passed, with size
+ *						     @payload_size. If payload's size is equal
+ *						     or less, it will be copied here.
+ *
+ * Returns 0 if packet is received successfully, or negative error otherwise.
+ */
+int tracecmd_msg_recv_time_sync(struct tracecmd_msg_handle *msg_handle,
+				unsigned int *sync_protocol,
+				unsigned int *sync_msg_id,
+				unsigned int *payload_size, char **payload)
+{
+	struct tracecmd_msg msg;
+	int ret = -1;
+	int buf_size;
+
+	memset(&msg, 0, sizeof(msg));
+	ret = tracecmd_msg_recv(msg_handle->fd, &msg);
+	if (ret < 0)
+		goto out;
+
+	if (ntohl(msg.hdr.cmd) != MSG_TIME_SYNC) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	if (sync_protocol)
+		*sync_protocol = ntohl(msg.tsync.sync_protocol);
+	if (sync_msg_id)
+		*sync_msg_id = ntohl(msg.tsync.sync_msg_id);
+
+	buf_size = msg_buf_len(&msg);
+	if (buf_size < 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (buf_size && payload && payload_size) {
+		if (*payload_size) {
+			if (*payload_size < buf_size || *payload == NULL) {
+				ret = -ENOMEM;
+				goto out;
+			}
+			memcpy(*payload, msg.buf, buf_size);
+			goto out;
+		}
+
+		*payload = malloc(buf_size);
+		if (*payload == NULL) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		*payload_size = buf_size;
+		memcpy(*payload, msg.buf, buf_size);
+	}
+
+out:
+	msg_free(&msg);
+	return ret;
+}
+
 static int make_trace_resp(struct tracecmd_msg *msg, int page_size, int nr_cpus,
 			   unsigned int *ports, bool use_fifos,
-			   unsigned long long trace_id)
+			   unsigned long long trace_id,
+			   unsigned int tsync_proto,
+			   unsigned int tsync_port)
 {
 	int data_size;
 
@@ -940,7 +1215,11 @@ static int make_trace_resp(struct tracecmd_msg *msg, int page_size, int nr_cpus,
 	write_uints(msg->buf, data_size, ports, nr_cpus);
 
 	msg->hdr.size = htonl(ntohl(msg->hdr.size) + data_size);
-	msg->trace_resp.flags = use_fifos ? htonl(MSG_TRACE_USE_FIFOS) : htonl(0);
+	msg->trace_req.flags = use_fifos ? htonl(MSG_TRACE_USE_FIFOS) : htonl(0);
+	msg->trace_resp.flags = htonl(msg->trace_resp.flags);
+	msg->trace_resp.tsync_proto = htonl(tsync_proto);
+	msg->trace_resp.tsync_port = htonl(tsync_port);
+
 	msg->trace_resp.cpus = htonl(nr_cpus);
 	msg->trace_resp.page_size = htonl(page_size);
 	msg->trace_resp.trace_id = htonll(trace_id);
@@ -951,14 +1230,16 @@ static int make_trace_resp(struct tracecmd_msg *msg, int page_size, int nr_cpus,
 int tracecmd_msg_send_trace_resp(struct tracecmd_msg_handle *msg_handle,
 				 int nr_cpus, int page_size,
 				 unsigned int *ports, bool use_fifos,
-				 unsigned long long trace_id)
+				 unsigned long long trace_id,
+				 unsigned int tsync_proto,
+				 unsigned int tsync_port)
 {
 	struct tracecmd_msg msg;
 	int ret;
 
 	tracecmd_msg_init(MSG_TRACE_RESP, &msg);
 	ret = make_trace_resp(&msg, page_size, nr_cpus, ports,
-			      use_fifos, trace_id);
+			      use_fifos, trace_id, tsync_proto, tsync_port);
 	if (ret < 0)
 		return ret;
 
@@ -968,7 +1249,9 @@ int tracecmd_msg_send_trace_resp(struct tracecmd_msg_handle *msg_handle,
 int tracecmd_msg_recv_trace_resp(struct tracecmd_msg_handle *msg_handle,
 				 int *nr_cpus, int *page_size,
 				 unsigned int **ports, bool *use_fifos,
-				 unsigned long long *trace_id)
+				 unsigned long long *trace_id,
+				 unsigned int *tsync_proto,
+				 unsigned int *tsync_port)
 {
 	struct tracecmd_msg msg;
 	char *p, *buf_end;
@@ -994,6 +1277,8 @@ int tracecmd_msg_recv_trace_resp(struct tracecmd_msg_handle *msg_handle,
 	*nr_cpus = ntohl(msg.trace_resp.cpus);
 	*page_size = ntohl(msg.trace_resp.page_size);
 	*trace_id = ntohll(msg.trace_resp.trace_id);
+	*tsync_proto = ntohl(msg.trace_resp.tsync_proto);
+	*tsync_port = ntohl(msg.trace_resp.tsync_port);
 	*ports = calloc(*nr_cpus, sizeof(**ports));
 	if (!*ports) {
 		ret = -ENOMEM;
diff --git a/lib/trace-cmd/trace-timesync.c b/lib/trace-cmd/trace-timesync.c
new file mode 100644
index 00000000..0534b14f
--- /dev/null
+++ b/lib/trace-cmd/trace-timesync.c
@@ -0,0 +1,498 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (C) 2019, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
+ *
+ */
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <linux/vm_sockets.h>
+#include <linux/limits.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <dirent.h>
+#include <errno.h>
+#include <pthread.h>
+
+#include "trace-cmd.h"
+#include "tracefs.h"
+#include "event-utils.h"
+#include "trace-tsync-local.h"
+
+struct tsync_proto {
+	struct tsync_proto *next;
+	unsigned int proto_id;
+	int	weight;
+
+	int (*clock_sync_init)(struct tracecmd_time_sync *clock_context);
+	int (*clock_sync_free)(struct tracecmd_time_sync *clock_context);
+	int (*clock_sync_calc)(struct tracecmd_time_sync *clock_context,
+			       long long *offset, long long *timestamp);
+};
+
+static struct tsync_proto *tsync_proto_list;
+
+static struct tsync_proto *tsync_proto_find(unsigned int proto_id)
+{
+	struct tsync_proto *proto;
+
+	for (proto = tsync_proto_list; proto; proto = proto->next)
+		if (proto->proto_id == proto_id)
+			return proto;
+
+	return NULL;
+}
+
+int tracecmd_tsync_proto_register(unsigned int proto_id, int weight,
+				int (*init)(struct tracecmd_time_sync *),
+				int (*free)(struct tracecmd_time_sync *),
+				int (*calc)(struct tracecmd_time_sync *,
+					    long long *, long long *))
+{
+	struct tsync_proto *proto;
+
+	if (tsync_proto_find(proto_id))
+		return -1;
+	proto = calloc(1, sizeof(struct tsync_proto));
+	if (!proto)
+		return -1;
+	proto->proto_id = proto_id;
+	proto->weight = weight;
+	proto->clock_sync_init = init;
+	proto->clock_sync_free = free;
+	proto->clock_sync_calc = calc;
+
+	proto->next = tsync_proto_list;
+	tsync_proto_list = proto;
+	return 0;
+}
+
+int tracecmd_tsync_proto_unregister(unsigned int proto_id)
+{
+	struct tsync_proto **last = &tsync_proto_list;
+
+	for (; *last; last = &(*last)->next) {
+		if ((*last)->proto_id == proto_id) {
+			struct tsync_proto *proto = *last;
+
+			*last = proto->next;
+			free(proto);
+			return 0;
+		}
+	}
+
+	return -1;
+}
+
+bool tsync_proto_is_supported(unsigned int proto_id)
+{
+	if (tsync_proto_find(proto_id))
+		return true;
+	return false;
+}
+
+/**
+ * tracecmd_tsync_get_offsets - Return the calculated time offsets
+ *
+ * @tsync: Pointer to time sync context
+ * @count: Returns the number of calculated time offsets
+ * @ts: Array of size @count containing timestamps of callculated offsets
+ * @offsets: array of size @count, containing offsets for each timestamp
+ *
+ * Retuns -1 in case of an error, or 0 otherwise
+ */
+int tracecmd_tsync_get_offsets(struct tracecmd_time_sync *tsync,
+				int *count,
+				long long **ts, long long **offsets)
+{
+	struct clock_sync_context *tsync_context;
+
+	if (!tsync || !tsync->context)
+		return -1;
+	tsync_context = (struct clock_sync_context *)tsync->context;
+	if (count)
+		*count = tsync_context->sync_count;
+	if (ts)
+		*ts = tsync_context->sync_ts;
+	if (offsets)
+		*offsets = tsync_context->sync_offsets;
+	return 0;
+}
+
+
+#define PROTO_MASK_SIZE (sizeof(char))
+/**
+ * tracecmd_tsync_proto_select - Select time sync protocol, to be used for
+ *		timestamp synchronization with a peer
+ *
+ * @proto_mask: bitmask array of time sync protocols, supported by the peer
+ * @length: size of the @protos array
+ *
+ * Retuns Id of a time sync protocol, that can be used with the peer, or 0
+ *	  in case there is no match with supported protocols
+ */
+unsigned int tracecmd_tsync_proto_select(char *proto_mask, int length)
+{
+	struct tsync_proto *selected = NULL;
+	struct tsync_proto *proto;
+	int word;
+	int id;
+
+	for (word = 0; word < length; word++) {
+		for (proto = tsync_proto_list; proto; proto = proto->next) {
+			if (proto->proto_id < word * PROTO_MASK_SIZE)
+				continue;
+
+			id = proto->proto_id - word * PROTO_MASK_SIZE;
+			if (id >= PROTO_MASK_SIZE)
+				continue;
+
+			if ((1 << id) & proto_mask[word]) {
+				if (selected) {
+					if (selected->weight < proto->weight)
+						selected = proto;
+				} else
+					selected = proto;
+			}
+		}
+	}
+
+	if (selected)
+		return selected->proto_id;
+
+	return 0;
+}
+
+/**
+ * tracecmd_tsync_proto_getall - Returns bitmask of all supported
+ *				 time sync protocols
+ * @proto_mask: return, allocated bitmask array of time sync protocols,
+ *	       supported by the peer. Must be freed by free()
+ * @words: return, allocated size of the @protobits array
+ *
+ * If completed successfully 0 is returned and allocated array in @proto_mask of
+ * size @words. In case of an error, -1 is returned.
+ * @proto_mask must be freed with free()
+ */
+int tracecmd_tsync_proto_getall(char **proto_mask, int *words)
+{
+	struct tsync_proto *proto;
+	int proto_max = 0;
+	int count = 0;
+	char *protos;
+
+	for (proto = tsync_proto_list; proto; proto = proto->next)
+		if (proto->proto_id > proto_max)
+			proto_max = proto->proto_id;
+
+	count = proto_max / PROTO_MASK_SIZE + 1;
+	protos = calloc(count, sizeof(char));
+	if (!protos)
+		return -1;
+
+	for (proto = tsync_proto_list; proto; proto = proto->next) {
+		if ((proto->proto_id / PROTO_MASK_SIZE) >= count)
+			continue;
+		protos[proto->proto_id / PROTO_MASK_SIZE] |=
+				(1 << (proto->proto_id % PROTO_MASK_SIZE));
+	}
+
+	*proto_mask = protos;
+	*words = count;
+	return 0;
+}
+
+static int get_vsocket_params(int fd, unsigned int *lcid, unsigned int *lport,
+			      unsigned int *rcid, unsigned int *rport)
+{
+	struct sockaddr_vm addr;
+	socklen_t addr_len = sizeof(addr);
+
+	memset(&addr, 0, sizeof(addr));
+	if (getsockname(fd, (struct sockaddr *)&addr, &addr_len))
+		return -1;
+	if (addr.svm_family != AF_VSOCK)
+		return -1;
+	*lport = addr.svm_port;
+	*lcid = addr.svm_cid;
+
+	memset(&addr, 0, sizeof(addr));
+	addr_len = sizeof(addr);
+	if (getpeername(fd, (struct sockaddr *)&addr, &addr_len))
+		return -1;
+	if (addr.svm_family != AF_VSOCK)
+		return -1;
+	*rport = addr.svm_port;
+	*rcid = addr.svm_cid;
+
+	return 0;
+}
+
+static struct tracefs_instance *
+clock_synch_create_instance(const char *clock, unsigned int cid)
+{
+	struct tracefs_instance *instance;
+	char inst_name[256];
+
+	snprintf(inst_name, 256, "clock_synch-%d", cid);
+
+	instance = tracefs_instance_alloc(inst_name);
+	if (!instance)
+		return NULL;
+
+	tracefs_instance_create(instance);
+	tracefs_instance_file_write(instance, "trace", "\0");
+	if (clock)
+		tracefs_instance_file_write(instance, "trace_clock", clock);
+	return instance;
+}
+
+static void
+clock_synch_delete_instance(struct tracefs_instance *inst)
+{
+	if (!inst)
+		return;
+	tracefs_instance_destroy(inst);
+	tracefs_instance_free(inst);
+}
+
+static int clock_context_init(struct tracecmd_time_sync *tsync, bool server)
+{
+	struct clock_sync_context *clock = NULL;
+	struct tsync_proto *protocol;
+
+	if (tsync->context)
+		return 0;
+
+	protocol = tsync_proto_find(tsync->sync_proto);
+	if (!protocol)
+		return -1;
+
+	clock = calloc(1, sizeof(struct clock_sync_context));
+	if (!clock)
+		return -1;
+
+	clock->is_server = server;
+	if (get_vsocket_params(tsync->msg_handle->fd, &clock->local_cid,
+			       &clock->local_port, &clock->remote_cid,
+			       &clock->remote_port))
+		goto error;
+
+	clock->instance = clock_synch_create_instance(tsync->clock_str,
+						      clock->remote_cid);
+	if (!clock->instance)
+		goto error;
+
+	tsync->context = clock;
+	if (protocol->clock_sync_init && protocol->clock_sync_init(tsync) < 0)
+		goto error;
+
+	return 0;
+error:
+	tsync->context = NULL;
+	free(clock);
+	return -1;
+}
+
+/**
+ * tracecmd_tsync_free - Free time sync context, allocated by
+ *		tracecmd_tsync_with_host() or tracecmd_tsync_with_guest() APIs
+ *
+ * @tsync: Pointer to time sync context
+ *
+ */
+void tracecmd_tsync_free(struct tracecmd_time_sync *tsync)
+{
+	struct clock_sync_context *tsync_context;
+	struct tsync_proto *proto;
+
+	if (!tsync->context)
+		return;
+	tsync_context = (struct clock_sync_context *)tsync->context;
+
+	proto = tsync_proto_find(tsync->sync_proto);
+	if (proto && proto->clock_sync_free)
+		proto->clock_sync_free(tsync);
+
+	clock_synch_delete_instance(tsync_context->instance);
+	tsync_context->instance = NULL;
+
+	free(tsync_context->sync_ts);
+	free(tsync_context->sync_offsets);
+	tsync_context->sync_ts = NULL;
+	tsync_context->sync_offsets = NULL;
+	tsync_context->sync_count = 0;
+	tsync_context->sync_size = 0;
+	pthread_mutex_destroy(&tsync->lock);
+	pthread_cond_destroy(&tsync->cond);
+	free(tsync->clock_str);
+}
+
+int tracecmd_tsync_send(struct tracecmd_time_sync *tsync,
+				  struct tsync_proto *proto)
+{
+	long long timestamp = 0;
+	long long offset = 0;
+	int ret;
+
+	ret = proto->clock_sync_calc(tsync, &offset, &timestamp);
+
+	return ret;
+}
+
+/**
+ * tracecmd_tsync_with_host - Synchronize timestamps with host
+ *
+ * @tsync: Pointer to time sync context
+ *
+ * This API is supposed to be called in guest context. It waits for a time
+ * sync request from the host and replies with a time sample, until time sync
+ * stop command is received
+ *
+ */
+void tracecmd_tsync_with_host(struct tracecmd_time_sync *tsync)
+{
+	struct tsync_proto *proto;
+	unsigned int protocol;
+	unsigned int command;
+	int ret;
+
+	proto = tsync_proto_find(tsync->sync_proto);
+	if (!proto || !proto->clock_sync_calc)
+		return;
+
+	clock_context_init(tsync, true);
+	if (!tsync->context)
+		return;
+
+	while (true) {
+		ret = tracecmd_msg_recv_time_sync(tsync->msg_handle,
+						  &protocol, &command,
+						  NULL, NULL);
+
+		if (ret ||
+		    protocol != TRACECMD_TIME_SYNC_PROTO_NONE ||
+		    command != TRACECMD_TIME_SYNC_CMD_PROBE)
+			break;
+		ret = tracecmd_tsync_send(tsync, proto);
+		if (ret)
+			break;
+	}
+}
+
+static int tsync_get_sample(struct tracecmd_time_sync *tsync,
+			    struct tsync_proto *proto, int array_step)
+{
+	struct clock_sync_context *clock;
+	long long *sync_offsets = NULL;
+	long long *sync_ts = NULL;
+	long long timestamp = 0;
+	long long offset = 0;
+	int ret;
+
+	ret = proto->clock_sync_calc(tsync, &offset, &timestamp);
+	if (ret) {
+		warning("Failed to synchronize timestamps with guest");
+		return -1;
+	}
+	if (!offset || !timestamp)
+		return 0;
+	clock = tsync->context;
+	if (clock->sync_count >= clock->sync_size) {
+		sync_ts = realloc(clock->sync_ts,
+				  (clock->sync_size + array_step) * sizeof(long long));
+		sync_offsets = realloc(clock->sync_offsets,
+				       (clock->sync_size + array_step) * sizeof(long long));
+		if (!sync_ts || !sync_offsets) {
+			free(sync_ts);
+			free(sync_offsets);
+			return -1;
+		}
+		clock->sync_size += array_step;
+		clock->sync_ts = sync_ts;
+		clock->sync_offsets = sync_offsets;
+	}
+
+	clock->sync_ts[clock->sync_count] = timestamp;
+	clock->sync_offsets[clock->sync_count] = offset;
+	clock->sync_count++;
+
+	return 0;
+}
+
+#define TIMER_SEC_NANO 1000000000LL
+static inline void get_ts_loop_delay(struct timespec *timeout, int delay_ms)
+{
+	memset(timeout, 0, sizeof(struct timespec));
+	clock_gettime(CLOCK_REALTIME, timeout);
+
+	timeout->tv_nsec += ((unsigned long long)delay_ms * 1000000LL);
+
+	if (timeout->tv_nsec >= TIMER_SEC_NANO) {
+		timeout->tv_sec += timeout->tv_nsec / TIMER_SEC_NANO;
+		timeout->tv_nsec %= TIMER_SEC_NANO;
+	}
+}
+
+#define CLOCK_TS_ARRAY 5
+/**
+ * tracecmd_tsync_with_guest - Synchronize timestamps with guest
+ *
+ * @tsync: Pointer to time sync context
+ *
+ * This API is supposed to be called in host context, in a separate thread
+ * It loops infinite, until the timesync semaphore is released
+ *
+ */
+void tracecmd_tsync_with_guest(struct tracecmd_time_sync *tsync)
+{
+	int ts_array_size = CLOCK_TS_ARRAY;
+	struct tsync_proto *proto;
+	struct timespec timeout;
+	bool end = false;
+	int ret;
+
+	proto = tsync_proto_find(tsync->sync_proto);
+	if (!proto || !proto->clock_sync_calc)
+		return;
+
+	clock_context_init(tsync, false);
+	if (!tsync->context)
+		return;
+
+	if (tsync->loop_interval > 0 &&
+	    tsync->loop_interval < (CLOCK_TS_ARRAY * 1000))
+		ts_array_size = (CLOCK_TS_ARRAY * 1000) / tsync->loop_interval;
+
+	while (true) {
+		pthread_mutex_lock(&tsync->lock);
+		ret = tracecmd_msg_send_time_sync(tsync->msg_handle,
+						  TRACECMD_TIME_SYNC_PROTO_NONE,
+						  TRACECMD_TIME_SYNC_CMD_PROBE,
+						  0, NULL);
+		ret = tsync_get_sample(tsync, proto, ts_array_size);
+		if (ret || end)
+			break;
+		if (tsync->loop_interval > 0) {
+			get_ts_loop_delay(&timeout, tsync->loop_interval);
+			ret = pthread_cond_timedwait(&tsync->cond, &tsync->lock, &timeout);
+			pthread_mutex_unlock(&tsync->lock);
+			if (ret && ret != ETIMEDOUT)
+				break;
+			else if (!ret)
+				end = true;
+		} else {
+			pthread_cond_wait(&tsync->cond, &tsync->lock);
+			end = true;
+			pthread_mutex_unlock(&tsync->lock);
+		}
+	};
+
+	tracecmd_msg_send_time_sync(tsync->msg_handle,
+				    TRACECMD_TIME_SYNC_PROTO_NONE,
+				    TRACECMD_TIME_SYNC_CMD_STOP,
+				    0, NULL);
+}
diff --git a/tracecmd/Makefile b/tracecmd/Makefile
index 0976341c..17e67600 100644
--- a/tracecmd/Makefile
+++ b/tracecmd/Makefile
@@ -31,6 +31,7 @@ TRACE_CMD_OBJS += trace-show.o
 TRACE_CMD_OBJS += trace-list.o
 TRACE_CMD_OBJS += trace-usage.o
 TRACE_CMD_OBJS += trace-dump.o
+TRACE_CMD_OBJS += trace-tsync.o
 
 ifeq ($(VSOCK_DEFINED), 1)
 TRACE_CMD_OBJS += trace-agent.o
@@ -43,7 +44,7 @@ all_objs := $(sort $(ALL_OBJS))
 all_deps := $(all_objs:$(bdir)/%.o=$(bdir)/.%.d)
 
 CONFIG_INCLUDES =
-CONFIG_LIBS	= -lrt
+CONFIG_LIBS	= -lrt -lpthread
 CONFIG_FLAGS	=
 
 all: $(TARGETS)
diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index 95d0026b..49c52b17 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -229,6 +229,10 @@ struct buffer_instance {
 	unsigned int		port;
 	int			*fds;
 	bool			use_fifos;
+
+	pthread_t		tsync_thread;
+	bool			tsync_thread_running;
+	struct tracecmd_time_sync tsync;
 };
 
 void init_top_instance(void);
@@ -263,6 +267,13 @@ void tracecmd_disable_tracing(void);
 void tracecmd_enable_tracing(void);
 void tracecmd_stat_cpu(struct trace_seq *s, int cpu);
 
+int tracecmd_host_tsync(struct buffer_instance *instance,
+			 unsigned int tsync_port);
+void tracecmd_host_tsync_complete(struct buffer_instance *instance);
+unsigned int tracecmd_guest_tsync(char *tsync_protos,
+				  unsigned int tsync_protos_size, char *clock,
+				  unsigned int *tsync_port, pthread_t *thr_id);
+
 int trace_make_vsock(unsigned int port);
 int trace_get_vsock_port(int sd, unsigned int *port);
 int trace_open_vsock(unsigned int cid, unsigned int port);
diff --git a/tracecmd/trace-agent.c b/tracecmd/trace-agent.c
index a8ef0852..b5816966 100644
--- a/tracecmd/trace-agent.c
+++ b/tracecmd/trace-agent.c
@@ -19,6 +19,7 @@
 #include <sys/wait.h>
 #include <unistd.h>
 #include <linux/vm_sockets.h>
+#include <pthread.h>
 
 #include "trace-local.h"
 #include "trace-msg.h"
@@ -125,11 +126,30 @@ cleanup:
 	return ret;
 }
 
+static char *get_clock(int argc, char **argv)
+{
+	int i;
+
+	if (!argc || !argv)
+		return NULL;
+
+	for (i = 0; i < argc - 1; i++) {
+		if (!strcmp("-C", argv[i]))
+			return argv[i+1];
+	}
+	return NULL;
+}
+
 static void agent_handle(int sd, int nr_cpus, int page_size)
 {
 	struct tracecmd_msg_handle *msg_handle;
+	unsigned int tsync_protos_size = 0;
+	unsigned int tsync_proto = 0;
 	unsigned long long trace_id;
+	unsigned int tsync_port = 0;
+	char *tsync_protos = NULL;
 	unsigned int *ports;
+	pthread_t sync_thr;
 	char **argv = NULL;
 	int argc = 0;
 	bool use_fifos;
@@ -146,7 +166,8 @@ static void agent_handle(int sd, int nr_cpus, int page_size)
 		die("Failed to allocate message handle");
 
 	ret = tracecmd_msg_recv_trace_req(msg_handle, &argc, &argv,
-					  &use_fifos, &trace_id);
+					  &use_fifos, &trace_id,
+					  &tsync_protos, &tsync_protos_size);
 	if (ret < 0)
 		die("Failed to receive trace request");
 
@@ -155,16 +176,28 @@ static void agent_handle(int sd, int nr_cpus, int page_size)
 
 	if (!use_fifos)
 		make_vsocks(nr_cpus, fds, ports);
-
+	if (tsync_protos) {
+		tsync_proto = tracecmd_guest_tsync(tsync_protos,
+						   tsync_protos_size,
+						   get_clock(argc, argv),
+						   &tsync_port, &sync_thr);
+		if (!tsync_proto)
+			warning("Failed to negotiate timestamps synchronization with the host");
+	}
 	trace_id = tracecmd_generate_traceid();
 	ret = tracecmd_msg_send_trace_resp(msg_handle, nr_cpus, page_size,
-					   ports, use_fifos, trace_id);
+					   ports, use_fifos, trace_id,
+					   tsync_proto, tsync_port);
 	if (ret < 0)
 		die("Failed to send trace response");
 
 	trace_record_agent(msg_handle, nr_cpus, fds, argc, argv,
 			   use_fifos, trace_id);
 
+	if (tsync_proto)
+		pthread_join(sync_thr, NULL);
+
+	free(tsync_protos);
 	free(argv[0]);
 	free(argv);
 	free(ports);
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 30ba5bb2..a60a5531 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -672,6 +672,11 @@ static void tell_guests_to_stop(void)
 			tracecmd_msg_send_close_msg(instance->msg_handle);
 	}
 
+	for_all_instances(instance) {
+		if (is_guest(instance))
+			tracecmd_host_tsync_complete(instance);
+	}
+
 	/* Wait for guests to acknowledge */
 	for_all_instances(instance) {
 		if (is_guest(instance)) {
@@ -3678,6 +3683,10 @@ static void connect_to_agent(struct buffer_instance *instance)
 {
 	struct tracecmd_msg_handle *msg_handle;
 	int sd, ret, nr_fifos, nr_cpus, page_size;
+	unsigned int tsync_protos_reply = 0;
+	unsigned int tsync_port = 0;
+	char *protos = NULL;
+	int protos_count = 0;
 	unsigned int *ports;
 	int i, *fds = NULL;
 	bool use_fifos = false;
@@ -3698,17 +3707,32 @@ static void connect_to_agent(struct buffer_instance *instance)
 	if (!msg_handle)
 		die("Failed to allocate message handle");
 
+	if (instance->tsync.loop_interval >= 0)
+		tracecmd_tsync_proto_getall(&protos, &protos_count);
+
 	ret = tracecmd_msg_send_trace_req(msg_handle, instance->argc,
 					  instance->argv, use_fifos,
-					  top_instance.trace_id);
+					  top_instance.trace_id,
+					  protos, protos_count);
 	if (ret < 0)
 		die("Failed to send trace request");
 
+	free(protos);
+
 	ret = tracecmd_msg_recv_trace_resp(msg_handle, &nr_cpus, &page_size,
 					   &ports, &use_fifos,
-					   &instance->trace_id);
+					   &instance->trace_id,
+					   &tsync_protos_reply, &tsync_port);
 	if (ret < 0)
-		die("Failed to receive trace response");
+		die("Failed to receive trace response %d", ret);
+
+	if (protos_count && tsync_protos_reply) {
+		if (tsync_proto_is_supported(tsync_protos_reply)) {
+			instance->tsync.sync_proto = tsync_protos_reply;
+			tracecmd_host_tsync(instance, tsync_port);
+		} else
+			warning("Failed to negotiate timestamps synchronization with the guest");
+	}
 
 	if (use_fifos) {
 		if (nr_cpus != nr_fifos) {
@@ -3756,7 +3780,8 @@ static void setup_guest(struct buffer_instance *instance)
 	close(fd);
 }
 
-static void setup_agent(struct buffer_instance *instance, struct common_record_context *ctx)
+static void setup_agent(struct buffer_instance *instance,
+			struct common_record_context *ctx)
 {
 	struct tracecmd_output *network_handle;
 
@@ -5281,6 +5306,7 @@ void init_top_instance(void)
 }
 
 enum {
+	OPT_tsyncinterval	= 242,
 	OPT_user		= 243,
 	OPT_procmap		= 244,
 	OPT_quiet		= 245,
@@ -5583,6 +5609,7 @@ static void parse_record_options(int argc,
 			{"proc-map", no_argument, NULL, OPT_procmap},
 			{"user", required_argument, NULL, OPT_user},
 			{"module", required_argument, NULL, OPT_module},
+			{"tsync-interval", required_argument, NULL, OPT_tsyncinterval},
 			{NULL, 0, NULL, 0}
 		};
 
@@ -5925,6 +5952,10 @@ static void parse_record_options(int argc,
 			ctx->instance->filter_mod = optarg;
 			ctx->filtered = 0;
 			break;
+		case OPT_tsyncinterval:
+			top_instance.tsync.loop_interval = atoi(optarg);
+			guest_sync_set = true;
+			break;
 		case OPT_quiet:
 		case 'q':
 			quiet = true;
@@ -5955,6 +5986,7 @@ static void parse_record_options(int argc,
 					add_argv(instance, "-C", true);
 				}
 			}
+			instance->tsync.loop_interval = top_instance.tsync.loop_interval;
 		}
 	}
 
diff --git a/tracecmd/trace-tsync.c b/tracecmd/trace-tsync.c
new file mode 100644
index 00000000..bf65e441
--- /dev/null
+++ b/tracecmd/trace-tsync.c
@@ -0,0 +1,272 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
+ *
+ */
+#include <stdlib.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <linux/vm_sockets.h>
+#include <pthread.h>
+
+#include "tracefs.h"
+#include "trace-local.h"
+#include "trace-msg.h"
+
+static int get_first_cpu(cpu_set_t **pin_mask, size_t *m_size)
+{
+	int cpus = tracecmd_count_cpus();
+	cpu_set_t *cpu_mask;
+	int mask_size;
+	int i;
+
+	cpu_mask = CPU_ALLOC(cpus);
+	*pin_mask = CPU_ALLOC(cpus);
+	if (!cpu_mask || !*pin_mask || 1)
+		goto error;
+
+	mask_size = CPU_ALLOC_SIZE(cpus);
+	CPU_ZERO_S(mask_size, cpu_mask);
+	CPU_ZERO_S(mask_size, *pin_mask);
+
+	if (sched_getaffinity(0, mask_size, cpu_mask) == -1)
+		goto error;
+
+	for (i = 0; i < cpus; i++) {
+		if (CPU_ISSET_S(i, mask_size, cpu_mask)) {
+			CPU_SET_S(i, mask_size, *pin_mask);
+			break;
+		}
+	}
+
+	if (CPU_COUNT_S(mask_size, *pin_mask) < 1)
+		goto error;
+
+	CPU_FREE(cpu_mask);
+	*m_size = mask_size;
+	return 0;
+
+error:
+	if (cpu_mask)
+		CPU_FREE(cpu_mask);
+	if (*pin_mask)
+		CPU_FREE(*pin_mask);
+	*pin_mask = NULL;
+	*m_size = 0;
+	return -1;
+}
+
+static void *tsync_host_thread(void *data)
+{
+	struct tracecmd_time_sync *tsync = NULL;
+
+	tsync = (struct tracecmd_time_sync *)data;
+
+	tracecmd_tsync_with_guest(tsync);
+
+	tracecmd_msg_handle_close(tsync->msg_handle);
+	tsync->msg_handle = NULL;
+
+	pthread_exit(0);
+}
+
+int tracecmd_host_tsync(struct buffer_instance *instance,
+			 unsigned int tsync_port)
+{
+	struct tracecmd_msg_handle *msg_handle = NULL;
+	cpu_set_t *pin_mask = NULL;
+	pthread_attr_t attrib;
+	size_t mask_size = 0;
+	int ret;
+	int fd;
+
+	if (!instance->tsync.sync_proto)
+		return -1;
+
+	fd = trace_open_vsock(instance->cid, tsync_port);
+	if (fd < 0) {
+		ret = -1;
+		goto out;
+	}
+	msg_handle = tracecmd_msg_handle_alloc(fd, 0);
+	if (!msg_handle) {
+		ret = -1;
+		goto out;
+	}
+
+	instance->tsync.msg_handle = msg_handle;
+	if (top_instance.clock)
+		instance->tsync.clock_str = strdup(top_instance.clock);
+	pthread_mutex_init(&instance->tsync.lock, NULL);
+	pthread_cond_init(&instance->tsync.cond, NULL);
+
+	pthread_attr_init(&attrib);
+	pthread_attr_setdetachstate(&attrib, PTHREAD_CREATE_JOINABLE);
+	if (!get_first_cpu(&pin_mask, &mask_size))
+		pthread_attr_setaffinity_np(&attrib, mask_size, pin_mask);
+
+	ret = pthread_create(&instance->tsync_thread, &attrib,
+			     tsync_host_thread, &instance->tsync);
+	if (!ret)
+		instance->tsync_thread_running = true;
+	if (pin_mask)
+		CPU_FREE(pin_mask);
+	pthread_attr_destroy(&attrib);
+
+out:
+	if (ret) {
+		if (msg_handle)
+			tracecmd_msg_handle_close(msg_handle);
+	}
+
+	return ret;
+}
+
+static void write_guest_time_shift(struct buffer_instance *instance)
+{
+	struct tracecmd_output *handle;
+	struct iovec vector[4];
+	long long *offsets;
+	long long *ts;
+	char *file;
+	int count;
+	int ret;
+	int fd;
+
+	ret = tracecmd_tsync_get_offsets(&instance->tsync, &count, &ts, &offsets);
+	if (ret < 0 || !count || !ts || !offsets)
+		return;
+
+	file = trace_get_guest_file(DEFAUT_INPUT_FILE,
+				tracefs_instance_get_name(instance->tracefs));
+	fd = open(file, O_RDWR);
+	if (fd < 0)
+		die("error opening %s", file);
+	free(file);
+	handle = tracecmd_get_output_handle_fd(fd);
+	vector[0].iov_len = 8;
+	vector[0].iov_base = &top_instance.trace_id;
+	vector[1].iov_len = 4;
+	vector[1].iov_base = &count;
+	vector[2].iov_len = 8 * count;
+	vector[2].iov_base = ts;
+	vector[3].iov_len = 8 * count;
+	vector[3].iov_base = offsets;
+	tracecmd_add_option_v(handle, TRACECMD_OPTION_TIME_SHIFT, vector, 4);
+	tracecmd_append_options(handle);
+	tracecmd_output_close(handle);
+#ifdef TSYNC_DEBUG
+	if (count > 1)
+		printf("Got %d timestamp synch samples for guest %s in %lld ns trace\n\r",
+			count, tracefs_instance_get_name(instance->tracefs),
+			ts[count - 1] - ts[0]);
+#endif
+}
+
+void tracecmd_host_tsync_complete(struct buffer_instance *instance)
+{
+	if (!instance->tsync_thread_running)
+		return;
+
+	/* Signal the time synchronization thread to complete and wait for it */
+	pthread_mutex_lock(&instance->tsync.lock);
+	pthread_cond_signal(&instance->tsync.cond);
+	pthread_mutex_unlock(&instance->tsync.lock);
+	pthread_join(instance->tsync_thread, NULL);
+	write_guest_time_shift(instance);
+	tracecmd_tsync_free(&instance->tsync);
+}
+
+static void *tsync_agent_thread(void *data)
+{
+	struct tracecmd_time_sync *tsync = NULL;
+	int sd;
+
+	tsync = (struct tracecmd_time_sync *)data;
+
+	while (true) {
+		sd = accept(tsync->msg_handle->fd, NULL, NULL);
+		if (sd < 0) {
+			if (errno == EINTR)
+				continue;
+			goto out;
+		}
+		break;
+	}
+	close(tsync->msg_handle->fd);
+	tsync->msg_handle->fd = sd;
+
+	tracecmd_tsync_with_host(tsync);
+
+out:
+	tracecmd_msg_handle_close(tsync->msg_handle);
+	tracecmd_tsync_free(tsync);
+	free(tsync);
+	close(sd);
+
+	pthread_exit(0);
+}
+
+unsigned int tracecmd_guest_tsync(char *tsync_protos,
+				  unsigned int tsync_protos_size, char *clock,
+				  unsigned int *tsync_port, pthread_t *thr_id)
+{
+	struct tracecmd_time_sync *tsync = NULL;
+	cpu_set_t *pin_mask = NULL;
+	pthread_attr_t attrib;
+	size_t mask_size = 0;
+	unsigned int proto;
+	int ret;
+	int fd;
+
+	fd = -1;
+	proto = tracecmd_tsync_proto_select(tsync_protos, tsync_protos_size);
+	if (!proto)
+		return 0;
+#ifdef VSOCK
+	fd = trace_make_vsock(VMADDR_PORT_ANY);
+	if (fd < 0)
+		goto error;
+
+	ret = trace_get_vsock_port(fd, tsync_port);
+	if (ret < 0)
+		goto error;
+#else
+	return 0;
+#endif
+
+	tsync = calloc(1, sizeof(struct tracecmd_time_sync));
+	tsync->msg_handle = tracecmd_msg_handle_alloc(fd, 0);
+	if (clock)
+		tsync->clock_str = strdup(clock);
+
+	pthread_attr_init(&attrib);
+	tsync->sync_proto = proto;
+	pthread_attr_setdetachstate(&attrib, PTHREAD_CREATE_JOINABLE);
+	if (!get_first_cpu(&pin_mask, &mask_size))
+		pthread_attr_setaffinity_np(&attrib, mask_size, pin_mask);
+
+	ret = pthread_create(thr_id, &attrib, tsync_agent_thread, tsync);
+
+	if (pin_mask)
+		CPU_FREE(pin_mask);
+	pthread_attr_destroy(&attrib);
+
+	if (ret)
+		goto error;
+
+	return proto;
+
+error:
+	if (tsync) {
+		if (tsync->msg_handle)
+			tracecmd_msg_handle_close(tsync->msg_handle);
+		free(tsync->clock_str);
+		free(tsync);
+	}
+	if (fd > 0)
+		close(fd);
+	return 0;
+}
diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c
index 502a4102..d43ca490 100644
--- a/tracecmd/trace-usage.c
+++ b/tracecmd/trace-usage.c
@@ -60,6 +60,10 @@ static struct usage_help usage_help[] = {
 		"          --no-filter include trace-cmd threads in the trace\n"
 		"          --proc-map save the traced processes address map into the trace.dat file\n"
 		"          --user execute the specified [command ...] as given user\n"
+		"          --tsync-interval set the loop interval, in ms, for timestamps synchronization with guests:"
+		"               If a negative number is specified, timestamps synchronization is disabled"
+		"               If 0 is specified, no loop is performed - timestamps offset is calculated only twice,"
+		"                                                         at the beginnig and at the end of the trace\n"
 	},
 	{
 		"start",
-- 
2.24.1

[PATCH v20 14/15] trace-cmd: [POC] PTP-like algorithm for host - guest timestamp synchronization

[Tzvetomir Stoyanov (VMware)]

PTP protocol is designed for synchronizing clocks of machines in a local network.
The same approach can be used for host - guest timestamp synchronization.
This implementation uses ftrace raw markers to track trace timestamps of PTP events.
The patch is a POC, two different algorithms for PTP calculations are proposed:
  - Choosing the sample with the fastest response time for calculating the clocks offset.
  - Calculating the clocks offset using the average of all PTP samples.

The implementation can be tuned using those parameters:
 - #define FASTEST_RESPONSE - is defined, the sample with the fastest response time
    is used for calculating the clocks offset. Otherwise the histogram of all samples is used.
 - #define PTP_SYNC_LOOP 340 - defines the number of samples, used for one calculation.
 - --tsync-interval - a trace-cmd argument, choose the intervals between offset calculations,
	performed continuously during the trace.
 - #define TSYNC_DEBUG - if defined, a debug information is collected and stored in files,
   in the guest machine:
     s-cid*.txt - For each offset calculation: host and guest clocks and calculated offset.
     res-cid*.txt - For each tracing session: all calculated clock offsets.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/trace-cmd/trace-cmd.h      |   1 +
 lib/trace-cmd/Makefile             |   1 +
 lib/trace-cmd/trace-timesync-ptp.c | 651 +++++++++++++++++++++++++++++
 lib/trace-cmd/trace-timesync.c     |   8 +
 tracecmd/trace-agent.c             |   2 +
 tracecmd/trace-record.c            |  23 +-
 6 files changed, 678 insertions(+), 8 deletions(-)
 create mode 100644 lib/trace-cmd/trace-timesync-ptp.c

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 42b47e2f..b5207248 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -414,6 +414,7 @@ int tracecmd_msg_recv_time_sync(struct tracecmd_msg_handle *msg_handle,
 
 enum{
 	TRACECMD_TIME_SYNC_PROTO_NONE	= 0,
+	TRACECMD_TIME_SYNC_PROTO_PTP	= 1,
 };
 enum{
 	TRACECMD_TIME_SYNC_CMD_PROBE	= 1,
diff --git a/lib/trace-cmd/Makefile b/lib/trace-cmd/Makefile
index ab7440ac..79672529 100644
--- a/lib/trace-cmd/Makefile
+++ b/lib/trace-cmd/Makefile
@@ -17,6 +17,7 @@ OBJS += trace-filter-hash.o
 OBJS += trace-msg.o
 OBJS += trace-plugin.o
 OBJS += trace-timesync.o
+OBJS += trace-timesync-ptp.o
 
 # Additional util objects
 OBJS += trace-blk-hack.o
diff --git a/lib/trace-cmd/trace-timesync-ptp.c b/lib/trace-cmd/trace-timesync-ptp.c
new file mode 100644
index 00000000..d1e2fae8
--- /dev/null
+++ b/lib/trace-cmd/trace-timesync-ptp.c
@@ -0,0 +1,651 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (C) 2019, VMware, Tzvetomir Stoyanov tz.stoyanov@gmail.com>
+ *
+ */
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <linux/vm_sockets.h>
+#include <sys/types.h>
+#include <linux/types.h>
+#include <time.h>
+#include <sched.h>
+#include "trace-cmd.h"
+#include "tracefs.h"
+#include "trace-tsync-local.h"
+#include "trace-msg.h"
+#include "trace-cmd-local.h"
+
+typedef __be32 be32;
+typedef __u64 u64;
+typedef __s64 s64;
+
+#define PTP_SYNC_LOOP	340
+
+#define PTP_SYNC_PKT_START	1
+#define PTP_SYNC_PKT_PROBE	2
+#define PTP_SYNC_PKT_PROBES	3
+#define PTP_SYNC_PKT_OFFSET	4
+#define PTP_SYNC_PKT_END	5
+
+#define TSYNC_DEBUG
+
+struct ptp_clock_sync {
+	struct tep_handle	*tep;
+	int			raw_id;
+	int			marker_fd;
+	int			series_id;
+	int			debug_fd;
+
+};
+
+struct ptp_clock_start_msg {
+	be32	series_id;
+} __attribute__((packed));
+
+struct ptp_clock_sample {
+	s64		ts;
+	be32		id;
+} __attribute__((packed));
+
+struct ptp_clock_result_msg {
+	be32			series_id;
+	be32			count;
+	struct ptp_clock_sample	samples[2*PTP_SYNC_LOOP];
+} __attribute__((packed));
+
+struct ptp_clock_offset_msg {
+	s64	ts;
+	s64	offset;
+};
+
+struct ptp_markers_context {
+	struct clock_sync_context	*clock;
+	struct ptp_clock_sync		*ptp;
+	int				size;
+	struct ptp_clock_result_msg	msg;
+};
+
+struct ptp_marker_buf {
+	int local_cid;
+	int remote_cid;
+	int count;
+	int packet_id;
+} __attribute__((packed));
+
+struct ptp_marker {
+	int series_id;
+	struct ptp_marker_buf data;
+} __attribute__((packed));
+
+static int ptp_clock_sync_init(struct tracecmd_time_sync *tsync)
+{
+	const char *systems[] = {"ftrace", NULL};
+	struct clock_sync_context *clock_context;
+	struct ptp_clock_sync *ptp;
+	struct tep_event *raw;
+	char *path;
+
+	if (!tsync || !tsync->context)
+		return -1;
+	clock_context = (struct clock_sync_context *)tsync->context;
+	if (clock_context->proto_data)
+		return 0;
+
+	ptp = calloc(1, sizeof(struct ptp_clock_sync));
+	if (!ptp)
+		return -1;
+
+	ptp->marker_fd = -1;
+	ptp->debug_fd = -1;
+
+	path = tracefs_instance_get_dir(clock_context->instance);
+	if (!path)
+		goto error;
+	ptp->tep = tracefs_local_events_system(path, systems);
+	tracefs_put_tracing_file(path);
+	if (!ptp->tep)
+		goto error;
+	raw = tep_find_event_by_name(ptp->tep, "ftrace", "raw_data");
+	if (!raw)
+		goto error;
+
+	ptp->raw_id = raw->id;
+	tep_set_file_bigendian(ptp->tep, tracecmd_host_bigendian());
+	tep_set_local_bigendian(ptp->tep, tracecmd_host_bigendian());
+
+	path = tracefs_instance_get_file(clock_context->instance, "trace_marker_raw");
+	if (!path)
+		goto error;
+	ptp->marker_fd = open(path, O_WRONLY);
+	tracefs_put_tracing_file(path);
+
+	clock_context->proto_data = ptp;
+
+#ifdef TSYNC_DEBUG
+	if (clock_context->is_server) {
+		char buff[256];
+		int res_fd;
+
+		sprintf(buff, "res-cid%d.txt", clock_context->remote_cid);
+
+		res_fd = open(buff, O_CREAT|O_WRONLY|O_TRUNC, 0644);
+		if (res_fd > 0)
+			close(res_fd);
+	}
+#endif
+
+	return 0;
+
+error:
+	if (ptp) {
+		tep_free(ptp->tep);
+		if (ptp->marker_fd >= 0)
+			close(ptp->marker_fd);
+	}
+	free(ptp);
+	return -1;
+}
+
+static int ptp_clock_sync_free(struct tracecmd_time_sync *tsync)
+{
+	struct clock_sync_context *clock_context;
+	struct ptp_clock_sync *ptp;
+
+	if (!tsync || !tsync->context)
+		return -1;
+	clock_context = (struct clock_sync_context *)tsync->context;
+
+	if (clock_context && clock_context->proto_data) {
+		ptp = (struct ptp_clock_sync *)clock_context->proto_data;
+		tep_free(ptp->tep);
+		if (ptp->marker_fd >= 0)
+			close(ptp->marker_fd);
+		if (ptp->debug_fd >= 0)
+			close(ptp->debug_fd);
+		free(clock_context->proto_data);
+		clock_context->proto_data = NULL;
+	}
+	return 0;
+}
+
+static int ptp_marker_find(struct tep_event *event, struct tep_record *record,
+			   int cpu, void *context)
+{
+	struct ptp_markers_context *ctx;
+	struct tep_format_field *field;
+	struct tep_format_field *id;
+	struct ptp_marker *marker;
+	int index = -1;
+
+	ctx = (struct ptp_markers_context *)context;
+
+	/* Make sure this is our event */
+	if (event->id != ctx->ptp->raw_id)
+		return 0;
+	id = tep_find_field(event, "id");
+	field = tep_find_field(event, "buf");
+	if (field && id &&
+	    record->size >= (id->offset + sizeof(struct ptp_marker))) {
+		marker = (struct ptp_marker *)(record->data + id->offset);
+		if (marker->data.local_cid == ctx->clock->local_cid &&
+		    marker->data.remote_cid == ctx->clock->remote_cid &&
+		    marker->series_id == ctx->ptp->series_id &&
+		    marker->data.count) {
+			if (marker->data.packet_id == 'r' &&
+			    marker->data.count <= ctx->size) {
+				index = marker->data.count - 1;
+			} else if (marker->data.packet_id == 's' &&
+				  marker->data.count*2 <= ctx->size){
+				index = ctx->size / 2 + marker->data.count - 1;
+			}
+		}
+		if (index >= 0) {
+			ctx->msg.samples[index].id = marker->data.count;
+			ctx->msg.samples[index].ts = record->ts;
+			ctx->msg.count++;
+		}
+	}
+
+	return 0;
+}
+
+//#define FASTEST_RESPONSE
+
+#ifdef FASTEST_RESPONSE
+static int ptp_calc_offset(struct clock_sync_context *clock,
+			   struct ptp_clock_result_msg *server,
+			   struct ptp_clock_result_msg *client,
+			   long long *offset_ret, long long *ts_ret,
+			   int *bad_probes)
+{
+	struct ptp_clock_sample *sample_send;
+	long long delta_min = 0;
+	long long offset = 0;
+	long long delta = 0;
+	long long ts = 0;
+	int i;
+
+	*bad_probes = 0;
+	sample_send = server->samples + (server->count / 2);
+	for (i = 0; i * 2 < server->count && i < client->count; i++) {
+		if (!server->samples[i].ts ||
+		    !sample_send[i].ts ||
+		    !client->samples[i].ts ||
+		    server->samples[i].id != sample_send[i].id ||
+		    server->samples[i].id != client->samples[i].id) {
+			(*bad_probes)++;
+			continue;
+		}
+
+		ts = (sample_send[i].ts + server->samples[i].ts) / 2;
+		offset = client->samples[i].ts - ts;
+
+		delta = server->samples[i].ts - sample_send[i].ts;
+		if (!delta_min || delta_min > delta) {
+			delta_min = delta;
+			*offset_ret = offset;
+			*ts_ret = ts;
+		}
+#ifdef TSYNC_DEBUG
+		{
+			struct ptp_clock_sync *ptp;
+
+			ptp = (struct ptp_clock_sync *)clock->proto_data;
+			if (ptp && ptp->debug_fd > 0) {
+				char buff[256];
+
+				sprintf(buff, "%lld %lld %lld\n",
+					ts, client->samples[i].ts, offset);
+				write(ptp->debug_fd, buff, strlen(buff));
+			}
+		}
+#endif
+	}
+
+	return 0;
+}
+
+#else /* histogram */
+
+static int ptp_calc_offset(struct clock_sync_context *clock,
+			   struct ptp_clock_result_msg *server,
+			   struct ptp_clock_result_msg *client,
+			   long long *offset_ret, long long *ts_ret,
+			   int *bad_probes)
+{
+	struct ptp_clock_sample *sample_send;
+	long long timestamps[PTP_SYNC_LOOP];
+	long long offsets[PTP_SYNC_LOOP];
+	int hist[PTP_SYNC_LOOP];
+	long long offset_max = 0;
+	long long offset_min = 0;
+	int ind, max = 0;
+	long long bin;
+	int i, k = 0;
+
+	*bad_probes = 0;
+	memset(hist, 0, sizeof(int) * PTP_SYNC_LOOP);
+	sample_send = server->samples + (server->count / 2);
+	for (i = 0; i * 2 < server->count && i < client->count; i++) {
+		if (!server->samples[i].ts ||
+		    !sample_send[i].ts ||
+		    !client->samples[i].ts ||
+		    server->samples[i].id != sample_send[i].id ||
+		    server->samples[i].id != client->samples[i].id) {
+			(*bad_probes)++;
+			continue;
+		}
+
+		timestamps[k] = (sample_send[i].ts + server->samples[i].ts) / 2;
+		offsets[k] = client->samples[i].ts - timestamps[k];
+		if (!offset_max || offset_max < llabs(offsets[k]))
+			offset_max = llabs(offsets[k]);
+		if (!offset_min || offset_min > llabs(offsets[k]))
+			offset_min = llabs(offsets[k]);
+#ifdef TSYNC_DEBUG
+		{
+			struct ptp_clock_sync *ptp;
+
+			ptp = (struct ptp_clock_sync *)clock->proto_data;
+
+			if (ptp && ptp->debug_fd > 0) {
+				char buff[256];
+
+				sprintf(buff, "%lld %lld %lld\n",
+					timestamps[k],
+					client->samples[i].ts, offsets[k]);
+				write(ptp->debug_fd, buff, strlen(buff));
+			}
+		}
+#endif
+		k++;
+	}
+
+	bin = (offset_max - offset_min) / PTP_SYNC_LOOP;
+	for (i = 0; i < k; i++) {
+		ind = (llabs(offsets[i]) - offset_min) / bin;
+		if (ind < PTP_SYNC_LOOP) {
+			hist[ind]++;
+			if (max < hist[ind]) {
+				max = hist[ind];
+				*offset_ret = offsets[i];
+				*ts_ret = timestamps[i];
+			}
+		}
+	}
+
+	return 0;
+}
+#endif
+
+static void ntoh_ptp_results(struct ptp_clock_result_msg *msg)
+{
+	int i;
+
+	msg->count = ntohl(msg->count);
+	for (i = 0; i < msg->count; i++) {
+		msg->samples[i].id = ntohl(msg->samples[i].id);
+		msg->samples[i].ts = ntohll(msg->samples[i].ts);
+	}
+	msg->series_id = ntohl(msg->series_id);
+}
+
+
+static void hton_ptp_results(struct ptp_clock_result_msg *msg)
+{
+	int i;
+
+	for (i = 0; i < msg->count; i++) {
+		msg->samples[i].id = htonl(msg->samples[i].id);
+		msg->samples[i].ts = htonll(msg->samples[i].ts);
+	}
+	msg->series_id = htonl(msg->series_id);
+	msg->count = htonl(msg->count);
+}
+
+static int ptp_clock_client(struct tracecmd_time_sync *tsync,
+			    long long *offset, long long *timestamp)
+{
+	struct clock_sync_context *clock_context;
+	struct ptp_clock_offset_msg res_offset;
+	unsigned int sync_proto, sync_msg;
+	struct ptp_clock_start_msg start;
+	struct ptp_markers_context ctx;
+	struct ptp_clock_sync *ptp;
+	struct ptp_marker marker;
+	unsigned int size;
+	char *msg;
+	int count;
+	int ret;
+
+	if (!tsync || !tsync->context || !tsync->msg_handle)
+		return -1;
+
+	clock_context = (struct clock_sync_context *)tsync->context;
+	if (clock_context->proto_data == NULL)
+		return -1;
+
+	ptp = (struct ptp_clock_sync *)clock_context->proto_data;
+	size = sizeof(start);
+	msg = (char *)&start;
+	ret = tracecmd_msg_recv_time_sync(tsync->msg_handle,
+					  &sync_proto, &sync_msg,
+					  &size, &msg);
+	if (ret || sync_proto != TRACECMD_TIME_SYNC_PROTO_PTP ||
+	    sync_msg != PTP_SYNC_PKT_START)
+		return -1;
+	ret = tracecmd_msg_send_time_sync(tsync->msg_handle,
+					  TRACECMD_TIME_SYNC_PROTO_PTP,
+					  PTP_SYNC_PKT_START, sizeof(start),
+					  (char *)&start);
+	marker.data.local_cid = clock_context->local_cid;
+	marker.data.remote_cid = clock_context->remote_cid;
+	marker.series_id = ntohl(start.series_id);
+	marker.data.packet_id = 'r';
+	ptp->series_id = marker.series_id;
+	msg = (char *)&count;
+	size = sizeof(count);
+	while (true) {
+		count = 0;
+		ret = tracecmd_msg_recv_time_sync(tsync->msg_handle,
+						  &sync_proto, &sync_msg,
+						  &size, &msg);
+		if (ret || sync_proto != TRACECMD_TIME_SYNC_PROTO_PTP ||
+		    sync_msg != PTP_SYNC_PKT_PROBE || !ntohl(count))
+			break;
+
+		marker.data.count = ntohl(count);
+		write(ptp->marker_fd, &marker, sizeof(marker));
+		ret = tracecmd_msg_send_time_sync(tsync->msg_handle,
+						 TRACECMD_TIME_SYNC_PROTO_PTP,
+						 PTP_SYNC_PKT_PROBE,
+						 sizeof(count), (char *)&count);
+		if (ret)
+			break;
+	}
+
+	if (sync_proto != TRACECMD_TIME_SYNC_PROTO_PTP ||
+	    sync_msg != PTP_SYNC_PKT_END)
+		return -1;
+
+	ctx.size = PTP_SYNC_LOOP;
+	ctx.ptp = ptp;
+	ctx.clock = clock_context;
+	ctx.msg.count = 0;
+	ctx.msg.series_id = ptp->series_id;
+	tracefs_iterate_raw_events(ptp->tep, clock_context->instance,
+				   ptp_marker_find, &ctx);
+	hton_ptp_results(&ctx.msg);
+	ret = tracecmd_msg_send_time_sync(tsync->msg_handle,
+					  TRACECMD_TIME_SYNC_PROTO_PTP,
+					  PTP_SYNC_PKT_PROBES,
+					  sizeof(ctx.msg), (char *)&ctx.msg);
+
+	msg = (char *)&res_offset;
+	size = sizeof(res_offset);
+	ret = tracecmd_msg_recv_time_sync(tsync->msg_handle,
+					  &sync_proto, &sync_msg,
+					  &size, (char **)&msg);
+	if (ret || sync_proto != TRACECMD_TIME_SYNC_PROTO_PTP ||
+	    sync_msg != PTP_SYNC_PKT_OFFSET)
+		return -1;
+
+	*offset = ntohll(res_offset.offset);
+	*timestamp = ntohll(res_offset.ts);
+
+	return 0;
+}
+
+
+static int ptp_clock_server(struct tracecmd_time_sync *tsync,
+			    long long *offset, long long *timestamp)
+{
+	struct ptp_clock_result_msg *results = NULL;
+	struct clock_sync_context *clock_context;
+	struct ptp_clock_offset_msg res_offset;
+	unsigned int sync_proto, sync_msg;
+	struct ptp_clock_start_msg start;
+	struct ptp_markers_context ctx;
+	int sync_loop = PTP_SYNC_LOOP;
+	struct ptp_clock_sync *ptp;
+	struct ptp_marker marker;
+	unsigned int size;
+	int bad_probes;
+	int count = 1;
+	int msg_count;
+	int msg_ret;
+	char *msg;
+	int ret;
+
+	if (!tsync || !tsync->context || !tsync->msg_handle)
+		return -1;
+
+	clock_context = (struct clock_sync_context *)tsync->context;
+	if (clock_context->proto_data == NULL)
+		return -1;
+
+	ptp = (struct ptp_clock_sync *)clock_context->proto_data;
+	start.series_id = htonl(ptp->series_id + 1);
+	ret = tracecmd_msg_send_time_sync(tsync->msg_handle,
+					 TRACECMD_TIME_SYNC_PROTO_PTP,
+					 PTP_SYNC_PKT_START, sizeof(start),
+					 (char *)&start);
+	if (!ret)
+		ret = tracecmd_msg_recv_time_sync(tsync->msg_handle,
+						  &sync_proto, &sync_msg,
+						  NULL, NULL);
+	if (ret || sync_proto != TRACECMD_TIME_SYNC_PROTO_PTP ||
+	    sync_msg != PTP_SYNC_PKT_START)
+		return -1;
+
+	tracefs_instance_file_write(clock_context->instance, "trace", "\0");
+
+	ptp->series_id++;
+	marker.data.local_cid = clock_context->local_cid;
+	marker.data.remote_cid = clock_context->remote_cid;
+	marker.series_id = ptp->series_id;
+	msg = (char *)&msg_ret;
+	size = sizeof(msg_ret);
+	do {
+		marker.data.count = count++;
+		marker.data.packet_id = 's';
+		msg_count = htonl(marker.data.count);
+		write(ptp->marker_fd, &marker, sizeof(marker));
+		ret = tracecmd_msg_send_time_sync(tsync->msg_handle,
+						 TRACECMD_TIME_SYNC_PROTO_PTP,
+						 PTP_SYNC_PKT_PROBE,
+						 sizeof(msg_count),
+						 (char *)&msg_count);
+		if (!ret)
+			ret = tracecmd_msg_recv_time_sync(tsync->msg_handle,
+							  &sync_proto, &sync_msg,
+							  &size, &msg);
+
+		marker.data.packet_id = 'r';
+		write(ptp->marker_fd, &marker, sizeof(marker));
+		if (ret || sync_proto != TRACECMD_TIME_SYNC_PROTO_PTP ||
+		    sync_msg != PTP_SYNC_PKT_PROBE ||
+		    ntohl(msg_ret) != marker.data.count)
+			break;
+	} while (--sync_loop);
+
+	if (sync_loop)
+		return -1;
+
+	ret = tracecmd_msg_send_time_sync(tsync->msg_handle,
+					  TRACECMD_TIME_SYNC_PROTO_PTP,
+					  PTP_SYNC_PKT_END, 0, NULL);
+
+	size = 0;
+	ret = tracecmd_msg_recv_time_sync(tsync->msg_handle,
+					  &sync_proto, &sync_msg,
+					  &size, (char **)&results);
+	if (ret || sync_proto != TRACECMD_TIME_SYNC_PROTO_PTP ||
+	    sync_msg != PTP_SYNC_PKT_PROBES || size == 0 || results == NULL)
+		return -1;
+
+	ntoh_ptp_results(results);
+
+	ctx.size = 2*PTP_SYNC_LOOP;
+	ctx.ptp = ptp;
+	ctx.clock = clock_context;
+	ctx.msg.count = 0;
+	ctx.msg.series_id = ptp->series_id;
+	tracefs_iterate_raw_events(ptp->tep, clock_context->instance,
+				   ptp_marker_find, &ctx);
+
+	ptp_calc_offset(clock_context, &ctx.msg, results, offset,
+			timestamp, &bad_probes);
+
+#ifdef TSYNC_DEBUG
+	{
+		char buff[256];
+		int res_fd;
+
+		sprintf(buff, "res-cid%d.txt", clock_context->remote_cid);
+
+		res_fd = open(buff, O_WRONLY|O_APPEND, 0644);
+		if (res_fd > 0) {
+			if (*offset && *timestamp) {
+				sprintf(buff, "%d %lld %lld\n",
+					ptp->series_id, *offset, *timestamp);
+				write(res_fd, buff, strlen(buff));
+			}
+			close(res_fd);
+		}
+
+		printf("\n calculated offset %d: %lld, %d probes, filtered out %d\n\r",
+			ptp->series_id, *offset, results->count, bad_probes);
+		if (ptp && ptp->debug_fd > 0) {
+			sprintf(buff, "%lld %lld 0\n", *offset, *timestamp);
+			write(ptp->debug_fd, buff, strlen(buff));
+			close(ptp->debug_fd);
+			ptp->debug_fd = -1;
+		}
+
+	}
+#endif
+
+	res_offset.offset = htonll(*offset);
+	res_offset.ts = htonll(*timestamp);
+	ret = tracecmd_msg_send_time_sync(tsync->msg_handle,
+					  TRACECMD_TIME_SYNC_PROTO_PTP,
+					  PTP_SYNC_PKT_OFFSET,
+					  sizeof(res_offset),
+					  (char *)&res_offset);
+
+	free(results);
+	return 0;
+}
+
+static int ptp_clock_sync_calc(struct tracecmd_time_sync *tsync,
+			       long long *offset, long long *timestamp)
+{
+	struct clock_sync_context *clock_context;
+	int ret;
+
+	if (!tsync || !tsync->context)
+		return -1;
+	clock_context = (struct clock_sync_context *)tsync->context;
+
+#ifdef TSYNC_DEBUG
+	if (clock_context->is_server) {
+		struct ptp_clock_sync *ptp;
+		char buff[256];
+
+		ptp = (struct ptp_clock_sync *)clock_context->proto_data;
+		if (ptp->debug_fd > 0)
+			close(ptp->debug_fd);
+		sprintf(buff, "s-cid%d_%d.txt",
+				clock_context->remote_cid, ptp->series_id+1);
+		ptp->debug_fd = open(buff, O_CREAT|O_WRONLY|O_TRUNC, 0644);
+	}
+#endif
+
+
+	if (clock_context->is_server)
+		ret = ptp_clock_server(tsync, offset, timestamp);
+	else
+		ret = ptp_clock_client(tsync, offset, timestamp);
+
+	return ret;
+}
+
+int ptp_clock_sync_register(void)
+{
+	return tracecmd_tsync_proto_register(TRACECMD_TIME_SYNC_PROTO_PTP,
+					     TRACECMD_TIME_SYNC_PROTO_PTP_WEIGHT,
+					     ptp_clock_sync_init,
+					     ptp_clock_sync_free,
+					     ptp_clock_sync_calc);
+
+}
+
+int ptp_clock_sync_unregister(void)
+{
+	return tracecmd_tsync_proto_unregister(TRACECMD_TIME_SYNC_PROTO_PTP);
+}
diff --git a/lib/trace-cmd/trace-timesync.c b/lib/trace-cmd/trace-timesync.c
index 0534b14f..68d53127 100644
--- a/lib/trace-cmd/trace-timesync.c
+++ b/lib/trace-cmd/trace-timesync.c
@@ -46,6 +46,14 @@ static struct tsync_proto *tsync_proto_find(unsigned int proto_id)
 	return NULL;
 }
 
+/**
+ * tracecmd_tsync_init - Initialize the global, per task, time sync data.
+ */
+void tracecmd_tsync_init(void)
+{
+	ptp_clock_sync_register();
+}
+
 int tracecmd_tsync_proto_register(unsigned int proto_id, int weight,
 				int (*init)(struct tracecmd_time_sync *),
 				int (*free)(struct tracecmd_time_sync *),
diff --git a/tracecmd/trace-agent.c b/tracecmd/trace-agent.c
index b5816966..2fd09dc3 100644
--- a/tracecmd/trace-agent.c
+++ b/tracecmd/trace-agent.c
@@ -247,6 +247,8 @@ static void agent_serve(unsigned int port)
 	if (sd < 0)
 		die("Failed to open vsocket");
 
+	tracecmd_tsync_init();
+
 	if (!get_local_cid(&cid))
 		printf("listening on @%u:%u\n", cid, port);
 
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index a60a5531..9b6b1945 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -6086,10 +6086,6 @@ static bool has_local_instances(void)
 	return false;
 }
 
-/*
- * This function contains common code for the following commands:
- * record, start, stream, profile.
- */
 static void record_trace(int argc, char **argv,
 			 struct common_record_context *ctx)
 {
@@ -6223,12 +6219,23 @@ static void record_trace(int argc, char **argv,
 	finalize_record_trace(ctx);
 }
 
+/*
+ * This function contains common code for the following commands:
+ * record, start, stream, profile.
+ */
+static void record_trace_command(int argc, char **argv,
+				 struct common_record_context *ctx)
+{
+	tracecmd_tsync_init();
+	record_trace(argc, argv, ctx);
+}
+
 void trace_start(int argc, char **argv)
 {
 	struct common_record_context ctx;
 
 	parse_record_options(argc, argv, CMD_start, &ctx);
-	record_trace(argc, argv, &ctx);
+	record_trace_command(argc, argv, &ctx);
 	exit(0);
 }
 
@@ -6308,7 +6315,7 @@ void trace_stream(int argc, char **argv)
 	struct common_record_context ctx;
 
 	parse_record_options(argc, argv, CMD_stream, &ctx);
-	record_trace(argc, argv, &ctx);
+	record_trace_command(argc, argv, &ctx);
 	exit(0);
 }
 
@@ -6327,7 +6334,7 @@ void trace_profile(int argc, char **argv)
 	if (!buffer_instances)
 		top_instance.flags |= BUFFER_FL_PROFILE;
 
-	record_trace(argc, argv, &ctx);
+	record_trace_command(argc, argv, &ctx);
 	do_trace_profile();
 	exit(0);
 }
@@ -6346,7 +6353,7 @@ void trace_record(int argc, char **argv)
 	struct common_record_context ctx;
 
 	parse_record_options(argc, argv, CMD_record, &ctx);
-	record_trace(argc, argv, &ctx);
+	record_trace_command(argc, argv, &ctx);
 	exit(0);
 }
 
-- 
2.24.1

[PATCH v20 15/15] trace-cmd: Debug scripts for PTP-like algorithm for host - guest timestamp synchronization

[Tzvetomir Stoyanov (VMware)]

These scripts can be used to visualise debug files, written when the PTP-like algorithm
is compiled with TSYNC_DEBUG defined. The files are located in the guest machine:
    s-cid*.txt - For each offset calculation: host and guest clocks and calculated offset.
    res-cid*.txt - For each tracing session: all calculated clock offsets.

tsync_hist.py plots a histogram, using data from a s-cid*.txt file:
	"python tsync_hist.py s-cid2_1.txt"
tsync_res.py plots a line, using data from res-cid*.txt file:
	"python tsync_res.py res-cid2.txt"

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 scripts/debug/tsync_hist.py | 57 +++++++++++++++++++++++++++++++++++++
 scripts/debug/tsync_readme  | 12 ++++++++
 scripts/debug/tsync_res.py  | 46 ++++++++++++++++++++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 scripts/debug/tsync_hist.py
 create mode 100644 scripts/debug/tsync_readme
 create mode 100644 scripts/debug/tsync_res.py

diff --git a/scripts/debug/tsync_hist.py b/scripts/debug/tsync_hist.py
new file mode 100644
index 00000000..819d1e8f
--- /dev/null
+++ b/scripts/debug/tsync_hist.py
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (C) 2019, VMware Inc, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
+# Copyright (C) 2019, VMware Inc, Yordan Karadzhov <ykaradzhov@vmware.com>
+
+
+import matplotlib.pyplot as plt
+import matplotlib.lines as mlines
+import numpy as np
+import sys
+
+def newline(p1, p2):
+    ax = plt.gca()
+    xmin, xmax = ax.get_xbound()
+
+    if(p2[0] == p1[0]):
+        xmin = xmax = p1[0]
+        ymin, ymax = ax.get_ybound()
+    else:
+        ymax = p1[1]+(p2[1]-p1[1])/(p2[0]-p1[0])*(xmax-p1[0])
+        ymin = p1[1]+(p2[1]-p1[1])/(p2[0]-p1[0])*(xmin-p1[0])
+
+    l = mlines.Line2D([xmin,xmax], [ymin,ymax], color='red')
+    ax.add_line(l)
+    return l
+
+
+data = np.loadtxt(fname = sys.argv[1])
+selected_ts  = data[-1, 1]
+selected_ofs = data[-1, 0]
+data = data[:-1,:]
+
+x = data[:, 1] - data[:, 0]
+
+mean = x.mean()
+std = x.std()
+
+num_bins = 500
+min = x.min() #+ .4 * (x.max() - x.min())
+max = x.max() #- .4 * (x.max() - x.min())
+bins = np.linspace(min, max, num_bins, endpoint = False, dtype=int)
+
+fig, ax = plt.subplots()
+
+# the histogram of the data
+n, bins, patches = ax.hist(x, bins, histtype=u'step');
+
+ax.set_xlabel('clock offset [$\mu$s]')
+ax.set_ylabel('entries')
+ax.set_title("$\sigma$=%i" % std)
+
+x1, y1 = [selected_ofs, min], [selected_ofs, max]
+newline(x1, y1)
+
+# Tweak spacing to prevent clipping of ylabel
+fig.tight_layout()
+plt.show()
diff --git a/scripts/debug/tsync_readme b/scripts/debug/tsync_readme
new file mode 100644
index 00000000..f3ebb25d
--- /dev/null
+++ b/scripts/debug/tsync_readme
@@ -0,0 +1,12 @@
+PTP-like algorithm debug
+========================
+
+tsync_*.py scripts can be used to visualise debug files, written when the PTP-like algorithm
+is compiled with TSYNC_DEBUG defined. The files are located in the guest machine:
+    s-cid*.txt - For each offset calculation: host and guest clocks and calculated offset.
+    res-cid*.txt - For each tracing session: all calculated clock offsets.
+
+tsync_hist.py plots a histogram, using data from a s-cid*.txt file:
+	"python tsync_hist.py s-cid2_1.txt"
+tsync_res.py plots a line, using data from res-cid*.txt file:
+	"python tsync_res.py res-cid2.txt"
diff --git a/scripts/debug/tsync_res.py b/scripts/debug/tsync_res.py
new file mode 100644
index 00000000..7d109863
--- /dev/null
+++ b/scripts/debug/tsync_res.py
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (C) 2019, VMware Inc, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
+# Copyright (C) 2019, VMware Inc, Yordan Karadzhov <ykaradzhov@vmware.com>
+
+
+import matplotlib.pyplot as plt
+import matplotlib.lines as mlines
+import numpy as np
+import sys
+
+def newline(p1, p2):
+    ax = plt.gca()
+    xmin, xmax = ax.get_xbound()
+
+    if(p2[0] == p1[0]):
+        xmin = xmax = p1[0]
+        ymin, ymax = ax.get_ybound()
+    else:
+        ymax = p1[1]+(p2[1]-p1[1])/(p2[0]-p1[0])*(xmax-p1[0])
+        ymin = p1[1]+(p2[1]-p1[1])/(p2[0]-p1[0])*(xmin-p1[0])
+
+    l = mlines.Line2D([xmin,xmax], [ymin,ymax], color='red')
+    ax.add_line(l)
+    return l
+
+data = np.loadtxt(fname = sys.argv[1])
+x = data[:, 0]
+y = data[:, 1]
+
+fig, ax = plt.subplots()
+
+ax.set_xlabel('samples (t)')
+ax.set_ylabel('clock offset')
+ax.set_title("$\delta$=%i ns" % (max(y) - min(y)))
+
+l = mlines.Line2D(x, y)
+ax.add_line(l)
+ax.set_xlim(min(x), max(x))
+ax.set_ylim(min(y), max(y) )
+
+print(min(y), max(y), max(y) - min(y))
+
+# Tweak spacing to prevent clipping of ylabel
+fig.tight_layout()
+plt.show()
-- 
2.24.1

Re: [PATCH v20 03/15] trace-cmd: Find and store pids of tasks, which run virtual CPUs of given VM

[Steven Rostedt]

On Thu, 27 Feb 2020 16:19:49 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> From: Tzvetomir Stoyanov <tstoyanov@vmware.com>
> 
> In order to match host and guest events, a mapping between guest VCPU
> and the host task, running this VCPU is needed. Extended existing
> struct guest to hold such mapping and added logic in read_qemu_guests()
> function to initialize it. Implemented a new internal API,
> get_guest_vcpu_pid(), to retrieve VCPU-task mapping for given VM.
> 
> Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
> ---
>  tracecmd/include/trace-local.h |  2 +
>  tracecmd/trace-record.c        | 77 ++++++++++++++++++++++++++++++++++
>  2 files changed, 79 insertions(+)
> 
> diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
> index 29f27793..a5cf0640 100644
> --- a/tracecmd/include/trace-local.h
> +++ b/tracecmd/include/trace-local.h
> @@ -247,6 +247,8 @@ void update_first_instance(struct buffer_instance *instance, int topt);
>  
>  void show_instance_file(struct buffer_instance *instance, const char *name);
>  
> +int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu);
> +
>  /* moved from trace-cmd.h */
>  void tracecmd_create_top_instance(char *name);
>  void tracecmd_remove_instances(void);
> diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> index 28fe31b7..4370c964 100644
> --- a/tracecmd/trace-record.c
> +++ b/tracecmd/trace-record.c
> @@ -3035,11 +3035,30 @@ struct guest {
>  	char *name;
>  	int cid;
>  	int pid;
> +	int cpu_max;
> +	int *cpu_pid;
>  };
>  
>  static struct guest *guests;
>  static size_t guests_len;
>  
> +static int set_vcpu_pid_mapping(struct guest *guest, int cpu, int pid)
> +{
> +	int *cpu_pid;
> +
> +	if (cpu < 0 || pid < 0)
> +		return -1;

This check makes the check before its call not needed (see below).

> +	if (cpu >= guest->cpu_max) {
> +		cpu_pid = realloc(guest->cpu_pid, (cpu + 1) * sizeof(int));

It is possible that the cpu numbers may be sparse, which means we should we
should probably initialize the new numbers as...

> +		if (!cpu_pid)
> +			return -1;

		/* Handle sparse CPU numbers */
		for (i = guest->cpu_max; i < cpu; i++)
			guest->cpu_pid[i] = -1;

Note, the above wont loop at all if there's no sparse CPUs (missing
numbers).

> +		guest->cpu_max = cpu + 1;
> +		guest->cpu_pid = cpu_pid;
> +	}
> +	guest->cpu_pid[cpu] = pid;
> +	return 0;
> +}
> +
>  static char *get_qemu_guest_name(char *arg)
>  {
>  	char *tok, *end = arg;
> @@ -3052,6 +3071,46 @@ static char *get_qemu_guest_name(char *arg)
>  	return arg;
>  }
>  
> +static void read_qemu_guests_pids(char *guest_task, struct guest *guest)

Probably should return a status.

> +{
> +	struct dirent *entry;
> +	char path[PATH_MAX];
> +	char *buf = NULL;
> +	size_t n = 0;
> +	long int vcpu;
> +	long int pid;

"int" is not needed. Just "long" is good enough.

	long vcpu;
	long pid;

Although, I doubt there will be more than 4 billion of either of these, so
they should probably be just "int". Which means you don't need the INT_MAX
checks.

> +	DIR *dir;
> +	FILE *f;
> +
> +	snprintf(path, sizeof(path), "/proc/%s/task", guest_task);
> +	dir = opendir(path);
> +	if (!dir)
> +		return;
> +
> +	while ((entry = readdir(dir))) {
> +		if (!(entry->d_type == DT_DIR && is_digits(entry->d_name)))
> +			continue;
> +
> +		snprintf(path, sizeof(path), "/proc/%s/task/%s/comm",
> +			 guest_task, entry->d_name);
> +		f = fopen(path, "r");
> +		if (!f)
> +			continue;
> +
> +		if (getline(&buf, &n, f) >= 0 &&
> +		    strncmp(buf, "CPU ", 4) == 0) {
> +			vcpu = strtol(buf + 4, NULL, 10);
> +			pid = strtol(entry->d_name, NULL, 10);
> +			if (vcpu < INT_MAX && pid < INT_MAX &&
> +			    vcpu >= 0 && pid >= 0)

The vcpu >= 0 && pid >= 0 are not needed due to the check in the function.

> +				set_vcpu_pid_mapping(guest, vcpu, pid);

Probably should check the return status of this function, and report a
warning if it fails.

> +		}
> +
> +		fclose(f);
> +	}
> +	free(buf);
> +}
> +
>  static void read_qemu_guests(void)
>  {
>  	static bool initialized;
> @@ -3115,6 +3174,8 @@ static void read_qemu_guests(void)
>  		if (!is_qemu)
>  			goto next;
>  
> +		read_qemu_guests_pids(entry->d_name, &guest);

Should probably check the status of the above function. Die on error?

> +
>  		guests = realloc(guests, (guests_len + 1) * sizeof(*guests));
>  		if (!guests)
>  			die("Can not allocate guest buffer");
> @@ -3160,6 +3221,22 @@ static char *parse_guest_name(char *guest, int *cid, int *port)
>  	return guest;
>  }
>  
> +int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu)
> +{
> +	int i;
> +
> +	if (!guests)
> +		return -1;
> +
> +	for (i = 0; i < guests_len; i++) {
> +		if (!guests[i].cpu_pid || guest_vcpu >= guests[i].cpu_max)

As a cpu_pid may be zero (unlikely), and the code I showed above
initialized sparse cpus as -1, then this should be guests[i].cpu_pid < 0.

-- Steve

> +			continue;
> +		if (guest_cid == guests[i].cid)
> +			return guests[i].cpu_pid[guest_vcpu];
> +	}
> +	return -1;
> +}
> +
>  static void set_prio(int prio)
>  {
>  	struct sched_param sp;

Re: [PATCH v20 09/15] trace-cmd: Implement new option in trace.dat file: TRACECMD_OPTION_TIME_SHIFT

[Steven Rostedt]

On Thu, 27 Feb 2020 16:19:55 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> +		case TRACECMD_OPTION_TIME_SHIFT:
> +			/*
> +			 * long long int (8 bytes) trace session ID
> +			 * int (4 bytes) count of timestamp offsets.
> +			 * long long array of size [count] of times,
> +			 *      when the offsets were calculated.
> +			 * long long array of size [count] of timestamp offsets.
> +			 */
> +			if (size < 12 || handle->flags & TRACECMD_FL_IGNORE_DATE)
> +				break;
> +			handle->host.trace_id = tep_read_number(handle->pevent,
> +								buf, 8);
> +			handle->host.ts_samples_count = tep_read_number(handle->pevent,
> +									buf + 8, 4);
> +			samples_size = (8 * handle->host.ts_samples_count);
> +			if (size != (12 + (2 * samples_size))) {
> +				warning("Failed to extract Time Shift information from the file, unexpected size %d", size);

Probably should show what was expected as well.

				warning("Failed to extract Time Shift information from the file: found size %d but expected %d",
					size, 12 + (2 * samples_size));

-- Steve

> +				break;
> +			}
> +			handle->host.ts_samples = malloc(2 * samples_size);
> +			if (!handle->host.ts_samples)
> +				return -ENOMEM;
> +			tsync_offset_load(handle, buf + 12);
> +			break;

Re: [PATCH v20 13/15] trace-cmd: Basic infrastructure for host - guest timestamp synchronization

[Steven Rostedt]

After applying this patch, my recordings stopped working. That's because
I'm still using fifos. I found the reason for this below.

On Thu, 27 Feb 2020 16:19:59 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> @@ -940,7 +1215,11 @@ static int make_trace_resp(struct tracecmd_msg *msg, int page_size, int nr_cpus,
>  	write_uints(msg->buf, data_size, ports, nr_cpus);
>  
>  	msg->hdr.size = htonl(ntohl(msg->hdr.size) + data_size);
> -	msg->trace_resp.flags = use_fifos ? htonl(MSG_TRACE_USE_FIFOS) : htonl(0);

> +	msg->trace_req.flags = use_fifos ? htonl(MSG_TRACE_USE_FIFOS) : htonl(0);
> +	msg->trace_resp.flags = htonl(msg->trace_resp.flags);

The above is what broke. That should be:

	msg->trace_resp.flags = use_fifos ? MSG_TRACE_USE_FIFOS : 0;
	msg->trace_resp.flags = htonl(msg->trace_resp.flags);

-- Steve


> +	msg->trace_resp.tsync_proto = htonl(tsync_proto);
> +	msg->trace_resp.tsync_port = htonl(tsync_port);
> +
>  	msg->trace_resp.cpus = htonl(nr_cpus);
>  	msg->trace_resp.page_size = htonl(page_size);
>  	msg->trace_resp.trace_id = htonll(trace_id);

Re: [PATCH v20 02/15] trace-cmd: Add new library API for local CPU count

[Steven Rostedt]

On Thu, 27 Feb 2020 16:19:48 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> In order to reuse the code, the function detecting the
> number of local CPU is moved from trace-cmd application to
> libtracecmd. The following new library API is introduced:
> 	int tracecmd_count_cpus(void);
> 
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
>

FYI,

I pulled in patch 1-2 of this series, so you don't need to resend those two.

I'm still looking at patch 14, but the rest look fine (besides what I
commented on). If you want to send the series again, please do. Just start
with patch 3 of this series and base it off of the latest master.

-- Steve

Re: [PATCH v20 13/15] trace-cmd: Basic infrastructure for host - guest timestamp synchronization

[Steven Rostedt]

Now that I'm playing with patch 14, I took more interest in this code.

On Thu, 27 Feb 2020 16:19:59 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> +
> +#define PROTO_MASK_SIZE (sizeof(char))

Hmm, this is the size in bytes of the mask, not bits. You may need both.

#define PROTO_MASK_BITS (PROTO_MASK_SIZE * 8)

Because we can have up to 8 protocols per mask size (8 bits in a byte).

> +/**
> + * tracecmd_tsync_proto_select - Select time sync protocol, to be used for
> + *		timestamp synchronization with a peer
> + *
> + * @proto_mask: bitmask array of time sync protocols, supported by the peer
> + * @length: size of the @protos array
> + *
> + * Retuns Id of a time sync protocol, that can be used with the peer, or 0
> + *	  in case there is no match with supported protocols
> + */
> +unsigned int tracecmd_tsync_proto_select(char *proto_mask, int length)
> +{
> +	struct tsync_proto *selected = NULL;
> +	struct tsync_proto *proto;
> +	int word;
> +	int id;
> +
> +	for (word = 0; word < length; word++) {
> +		for (proto = tsync_proto_list; proto; proto = proto->next) {
> +			if (proto->proto_id < word * PROTO_MASK_SIZE)
> +				continue;

The above should be: proto->proto_id < word * PROTO_MASK_BITS

Because what you have currently is:

   proto->proto_id < word * 1


> +
> +			id = proto->proto_id - word * PROTO_MASK_SIZE;

And here you want PROTO_MASK_BITS, otherwise if we have a proto_id of 2
(which would fit as a bit in a char), this would become:

	id = 2 - 0 * 1 = 1

> +			if (id >= PROTO_MASK_SIZE)

Then this is: 2 >= 1 which would skip it.

Hmm, maybe you don't even need PROTO_MASK_SIZE and only need
PROTO_MASK_BITS.

-- Steve

> +				continue;
> +
> +			if ((1 << id) & proto_mask[word]) {
> +				if (selected) {
> +					if (selected->weight < proto->weight)
> +						selected = proto;
> +				} else
> +					selected = proto;
> +			}
> +		}
> +	}
> +
> +	if (selected)
> +		return selected->proto_id;
> +
> +	return 0;
> +}
> +

Re: [PATCH v20 03/15] trace-cmd: Find and store pids of tasks, which run virtual CPUs of given VM

[Tzvetomir Stoyanov]

On Thu, Feb 27, 2020 at 7:23 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Thu, 27 Feb 2020 16:19:49 +0200
> "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
>
> > From: Tzvetomir Stoyanov <tstoyanov@vmware.com>
> >
> > In order to match host and guest events, a mapping between guest VCPU
> > and the host task, running this VCPU is needed. Extended existing
> > struct guest to hold such mapping and added logic in read_qemu_guests()
> > function to initialize it. Implemented a new internal API,
> > get_guest_vcpu_pid(), to retrieve VCPU-task mapping for given VM.
> >
> > Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
> > ---
> >  tracecmd/include/trace-local.h |  2 +
> >  tracecmd/trace-record.c        | 77 ++++++++++++++++++++++++++++++++++
> >  2 files changed, 79 insertions(+)
> >
> > diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
> > index 29f27793..a5cf0640 100644
> > --- a/tracecmd/include/trace-local.h
> > +++ b/tracecmd/include/trace-local.h
> > @@ -247,6 +247,8 @@ void update_first_instance(struct buffer_instance *instance, int topt);
> >
> >  void show_instance_file(struct buffer_instance *instance, const char *name);
> >
> > +int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu);
> > +
> >  /* moved from trace-cmd.h */
> >  void tracecmd_create_top_instance(char *name);
> >  void tracecmd_remove_instances(void);
> > diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> > index 28fe31b7..4370c964 100644
> > --- a/tracecmd/trace-record.c
> > +++ b/tracecmd/trace-record.c
> > @@ -3035,11 +3035,30 @@ struct guest {
> >       char *name;
> >       int cid;
> >       int pid;
> > +     int cpu_max;
> > +     int *cpu_pid;
> >  };
> >
> >  static struct guest *guests;
> >  static size_t guests_len;
> >
> > +static int set_vcpu_pid_mapping(struct guest *guest, int cpu, int pid)
> > +{
> > +     int *cpu_pid;
> > +
> > +     if (cpu < 0 || pid < 0)
> > +             return -1;
>
> This check makes the check before its call not needed (see below).
>
> > +     if (cpu >= guest->cpu_max) {
> > +             cpu_pid = realloc(guest->cpu_pid, (cpu + 1) * sizeof(int));
>
> It is possible that the cpu numbers may be sparse, which means we should we
> should probably initialize the new numbers as...
>
> > +             if (!cpu_pid)
> > +                     return -1;
>
>                 /* Handle sparse CPU numbers */
>                 for (i = guest->cpu_max; i < cpu; i++)
>                         guest->cpu_pid[i] = -1;
>
> Note, the above wont loop at all if there's no sparse CPUs (missing
> numbers).
>
> > +             guest->cpu_max = cpu + 1;
> > +             guest->cpu_pid = cpu_pid;
> > +     }
> > +     guest->cpu_pid[cpu] = pid;
> > +     return 0;
> > +}
> > +
> >  static char *get_qemu_guest_name(char *arg)
> >  {
> >       char *tok, *end = arg;
> > @@ -3052,6 +3071,46 @@ static char *get_qemu_guest_name(char *arg)
> >       return arg;
> >  }
> >
> > +static void read_qemu_guests_pids(char *guest_task, struct guest *guest)
>
> Probably should return a status.
>
> > +{
> > +     struct dirent *entry;
> > +     char path[PATH_MAX];
> > +     char *buf = NULL;
> > +     size_t n = 0;
> > +     long int vcpu;
> > +     long int pid;
>
> "int" is not needed. Just "long" is good enough.
>
>         long vcpu;
>         long pid;
>
> Although, I doubt there will be more than 4 billion of either of these, so
> they should probably be just "int". Which means you don't need the INT_MAX
> checks.
>
The reason I use long is strtol(), which returns long integer. In case
of an error, this API returns LONG_MAX or LONG_MIN.
The set_vcpu_pid_mapping() accepts int, that's why I put these checks
- to filter possible strtol() parsing errors and int overflow.
I'll keep the checks and remove the duplicated ones in set_vcpu_pid_mapping()

> > +     DIR *dir;
> > +     FILE *f;
> > +
> > +     snprintf(path, sizeof(path), "/proc/%s/task", guest_task);
> > +     dir = opendir(path);
> > +     if (!dir)
> > +             return;
> > +
> > +     while ((entry = readdir(dir))) {
> > +             if (!(entry->d_type == DT_DIR && is_digits(entry->d_name)))
> > +                     continue;
> > +
> > +             snprintf(path, sizeof(path), "/proc/%s/task/%s/comm",
> > +                      guest_task, entry->d_name);
> > +             f = fopen(path, "r");
> > +             if (!f)
> > +                     continue;
> > +
> > +             if (getline(&buf, &n, f) >= 0 &&
> > +                 strncmp(buf, "CPU ", 4) == 0) {
> > +                     vcpu = strtol(buf + 4, NULL, 10);
> > +                     pid = strtol(entry->d_name, NULL, 10);
> > +                     if (vcpu < INT_MAX && pid < INT_MAX &&
> > +                         vcpu >= 0 && pid >= 0)
>
> The vcpu >= 0 && pid >= 0 are not needed due to the check in the function.
>
> > +                             set_vcpu_pid_mapping(guest, vcpu, pid);
>
> Probably should check the return status of this function, and report a
> warning if it fails.
>
> > +             }
> > +
> > +             fclose(f);
> > +     }
> > +     free(buf);
> > +}
> > +
> >  static void read_qemu_guests(void)
> >  {
> >       static bool initialized;
> > @@ -3115,6 +3174,8 @@ static void read_qemu_guests(void)
> >               if (!is_qemu)
> >                       goto next;
> >
> > +             read_qemu_guests_pids(entry->d_name, &guest);
>
> Should probably check the status of the above function. Die on error?

I'll put a warning, as this failure is not critical - the guest
tracing will still work, even without this mapping.

Thanks, Steven!
>
> > +
> >               guests = realloc(guests, (guests_len + 1) * sizeof(*guests));
> >               if (!guests)
> >                       die("Can not allocate guest buffer");
> > @@ -3160,6 +3221,22 @@ static char *parse_guest_name(char *guest, int *cid, int *port)
> >       return guest;
> >  }
> >
> > +int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu)
> > +{
> > +     int i;
> > +
> > +     if (!guests)
> > +             return -1;
> > +
> > +     for (i = 0; i < guests_len; i++) {
> > +             if (!guests[i].cpu_pid || guest_vcpu >= guests[i].cpu_max)
>
> As a cpu_pid may be zero (unlikely), and the code I showed above
> initialized sparse cpus as -1, then this should be guests[i].cpu_pid < 0.
>
> -- Steve
>
> > +                     continue;
> > +             if (guest_cid == guests[i].cid)
> > +                     return guests[i].cpu_pid[guest_vcpu];
> > +     }
> > +     return -1;
> > +}
> > +
> >  static void set_prio(int prio)
> >  {
> >       struct sched_param sp;
>


--
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center

Re: [PATCH v20 13/15] trace-cmd: Basic infrastructure for host - guest timestamp synchronization

[Tzvetomir Stoyanov]

On Sat, Feb 29, 2020 at 2:28 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
>
> Now that I'm playing with patch 14, I took more interest in this code.
>
> On Thu, 27 Feb 2020 16:19:59 +0200
> "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
>
> > +
> > +#define PROTO_MASK_SIZE (sizeof(char))
>
> Hmm, this is the size in bytes of the mask, not bits. You may need both.
>
> #define PROTO_MASK_BITS (PROTO_MASK_SIZE * 8)
>
> Because we can have up to 8 protocols per mask size (8 bits in a byte).
>
> > +/**
> > + * tracecmd_tsync_proto_select - Select time sync protocol, to be used for
> > + *           timestamp synchronization with a peer
> > + *
> > + * @proto_mask: bitmask array of time sync protocols, supported by the peer
> > + * @length: size of the @protos array
> > + *
> > + * Retuns Id of a time sync protocol, that can be used with the peer, or 0
> > + *     in case there is no match with supported protocols
> > + */
> > +unsigned int tracecmd_tsync_proto_select(char *proto_mask, int length)
> > +{
> > +     struct tsync_proto *selected = NULL;
> > +     struct tsync_proto *proto;
> > +     int word;
> > +     int id;
> > +
> > +     for (word = 0; word < length; word++) {
> > +             for (proto = tsync_proto_list; proto; proto = proto->next) {
> > +                     if (proto->proto_id < word * PROTO_MASK_SIZE)
> > +                             continue;
>
> The above should be: proto->proto_id < word * PROTO_MASK_BITS
>
> Because what you have currently is:
>
>    proto->proto_id < word * 1
>
>
> > +
> > +                     id = proto->proto_id - word * PROTO_MASK_SIZE;
>
> And here you want PROTO_MASK_BITS, otherwise if we have a proto_id of 2
> (which would fit as a bit in a char), this would become:
>
>         id = 2 - 0 * 1 = 1
>
> > +                     if (id >= PROTO_MASK_SIZE)
>
> Then this is: 2 >= 1 which would skip it.
>
> Hmm, maybe you don't even need PROTO_MASK_SIZE and only need
> PROTO_MASK_BITS.
>
The PROTO_MASK_SIZE is the size of 1 word of the mask array, in bytes.
In the first implementation the array was of integers, and the define
was 4. It was very easy to switch to char, that's why I prefer to keep
the implementation as is - even though that "proto->proto_id < word *
1".
The confusion is the name of the variable "id", which is actually the
index of the bit inside the given bitmask's word. In the example of
proto_id 2:
  - the word is 0, this proto_id is in the first word from the bitmask array.
  - the index of the bit in this word is 2 ( id = 2 - 0 * 1 = 2 )
  - then we can check if the bit, representing the proto_id 2 is up:
        if ((1 << id) & proto_mask[word]) ...



> -- Steve
>
> > +                             continue;
> > +
> > +                     if ((1 << id) & proto_mask[word]) {
> > +                             if (selected) {
> > +                                     if (selected->weight < proto->weight)
> > +                                             selected = proto;
> > +                             } else
> > +                                     selected = proto;
> > +                     }
> > +             }
> > +     }
> > +
> > +     if (selected)
> > +             return selected->proto_id;
> > +
> > +     return 0;
> > +}
> > +



--
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center

Re: [PATCH v20 13/15] trace-cmd: Basic infrastructure for host - guest timestamp synchronization

[Steven Rostedt]

On Mon, 2 Mar 2020 11:43:52 +0200
Tzvetomir Stoyanov <tz.stoyanov@gmail.com> wrote:

> On Sat, Feb 29, 2020 at 2:28 AM Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> >
> > Now that I'm playing with patch 14, I took more interest in this code.
> >
> > On Thu, 27 Feb 2020 16:19:59 +0200
> > "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
> >  
> > > +
> > > +#define PROTO_MASK_SIZE (sizeof(char))  
> >
> > Hmm, this is the size in bytes of the mask, not bits. You may need both.
> >
> > #define PROTO_MASK_BITS (PROTO_MASK_SIZE * 8)
> >
> > Because we can have up to 8 protocols per mask size (8 bits in a byte).
> >  
> > > +/**
> > > + * tracecmd_tsync_proto_select - Select time sync protocol, to be used for
> > > + *           timestamp synchronization with a peer
> > > + *
> > > + * @proto_mask: bitmask array of time sync protocols, supported by the peer
> > > + * @length: size of the @protos array
> > > + *
> > > + * Retuns Id of a time sync protocol, that can be used with the peer, or 0
> > > + *     in case there is no match with supported protocols
> > > + */
> > > +unsigned int tracecmd_tsync_proto_select(char *proto_mask, int length)
> > > +{
> > > +     struct tsync_proto *selected = NULL;
> > > +     struct tsync_proto *proto;
> > > +     int word;
> > > +     int id;
> > > +
> > > +     for (word = 0; word < length; word++) {
> > > +             for (proto = tsync_proto_list; proto; proto = proto->next) {
> > > +                     if (proto->proto_id < word * PROTO_MASK_SIZE)
> > > +                             continue;  
> >
> > The above should be: proto->proto_id < word * PROTO_MASK_BITS
> >
> > Because what you have currently is:
> >
> >    proto->proto_id < word * 1
> >
> >  
> > > +
> > > +                     id = proto->proto_id - word * PROTO_MASK_SIZE;  
> >
> > And here you want PROTO_MASK_BITS, otherwise if we have a proto_id of 2
> > (which would fit as a bit in a char), this would become:
> >
> >         id = 2 - 0 * 1 = 1
> >  
> > > +                     if (id >= PROTO_MASK_SIZE)  
> >
> > Then this is: 2 >= 1 which would skip it.
> >
> > Hmm, maybe you don't even need PROTO_MASK_SIZE and only need
> > PROTO_MASK_BITS.
> >  
> The PROTO_MASK_SIZE is the size of 1 word of the mask array, in bytes.
> In the first implementation the array was of integers, and the define
> was 4. It was very easy to switch to char, that's why I prefer to keep
> the implementation as is - even though that "proto->proto_id < word *
> 1".
> The confusion is the name of the variable "id", which is actually the
> index of the bit inside the given bitmask's word. In the example of
> proto_id 2:
>   - the word is 0, this proto_id is in the first word from the bitmask array.
>   - the index of the bit in this word is 2 ( id = 2 - 0 * 1 = 2 )

Yes, 2 (that's what I meant), but then my point still is valid.

>   - then we can check if the bit, representing the proto_id 2 is up:
>         if ((1 << id) & proto_mask[word]) ...

I'm talking about this:

+			id = proto->proto_id - word * PROTO_MASK_SIZE;
+			if (id >= PROTO_MASK_SIZE)
+				continue;


Where id = 2, then if (2 >= 1) continue, means we skip it.

You need: if (id >= PROTO_MASK_SIZE_BITS)

-- Steve