From: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
To: rostedt@goodmis.org
Cc: linux-trace-devel@vger.kernel.org
Subject: [PATCH v14 13/19] trace-cmd: Implement new option in trace.dat file: TRACECMD_OPTION_TIME_SHIFT
Date: Wed, 27 Nov 2019 16:02:41 +0200 [thread overview]
Message-ID: <20191127140247.258766-14-tz.stoyanov@gmail.com> (raw)
In-Reply-To: <20191127140247.258766-1-tz.stoyanov@gmail.com>
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 | 6 ++
lib/trace-cmd/trace-input.c | 170 +++++++++++++++++++++++++++++++++-
2 files changed, 174 insertions(+), 2 deletions(-)
diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 90fa146..1240b4a 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -87,6 +87,7 @@ enum {
TRACECMD_OPTION_VERSION,
TRACECMD_OPTION_PROCMAPS,
TRACECMD_OPTION_TRACEID,
+ TRACECMD_OPTION_TIME_SHIFT,
};
enum {
@@ -130,6 +131,11 @@ 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);
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 40d9825..a6b675a 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -74,6 +74,18 @@ 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;
@@ -92,6 +104,7 @@ 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;
@@ -1072,6 +1085,67 @@ 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 tscor = min->offset +
+ (((((long long)ts) - min->time)*
+ (max->offset-min->offset))/(max->time-min->time));
+
+ 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 || !host->ts_samples_count || !host->ts_samples)
+ 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.
*/
@@ -1093,7 +1167,7 @@ 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;
@@ -1820,7 +1894,7 @@ 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;
@@ -2143,6 +2217,47 @@ 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;
+ 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;
@@ -2323,6 +2438,7 @@ static int handle_options(struct tracecmd_input *handle)
struct input_buffer_instance *buffer;
struct hook_list *hook;
char *buf;
+ int sampes_size;
int cpus;
/* By default, use usecs, unless told otherwise */
@@ -2370,6 +2486,28 @@ 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);
+ sampes_size = (8 * handle->host.ts_samples_count);
+ if (size != (12 + (2 * sampes_size)))
+ break;
+ handle->host.ts_samples = malloc(2 * sampes_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);
@@ -3078,6 +3216,8 @@ 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 {
@@ -3532,3 +3672,29 @@ 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
+ */
+void tracecmd_enable_tsync(struct tracecmd_input *handle, bool enable)
+{
+ handle->host.sync_enable = enable;
+}
--
2.23.0
next prev parent reply other threads:[~2019-11-27 14:03 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-27 14:02 [PATCH v14 00/19] Timestamp synchronization of host - guest Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 01/19] trace-cmd: Implement new lib API: tracecmd_local_events_system() Tzvetomir Stoyanov (VMware)
2019-12-04 14:59 ` Steven Rostedt
2019-11-27 14:02 ` [PATCH v14 02/19] trace-cmd: Add support for negative time offsets in trace.dat file Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 03/19] trace-cmd: Add implementations of htonll() and ntohll() Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 04/19] trace-cmd: Add new library APIs for ftrace instances Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 05/19] trace-cmd: Add new library API for local CPU count Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 06/19] trace-cmd: Add new library API for reading ftrace buffers Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 07/19] trace-cmd: Find and store pids of tasks, which run virtual CPUs of given VM Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 08/19] trace-cmd: --del the tracee address map into the guest's trace.dat file Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 09/19] trace-cmd: Implement new API tracecmd_add_option_v() Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 10/19] trace-cmd: Add new API to generate a unique ID of the tracing session Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 11/19] trace-cmd: Store the session tracing ID in the trace.dat file Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 12/19] trace-cmd: Exchange tracing IDs between host and guest Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` Tzvetomir Stoyanov (VMware) [this message]
2019-11-27 14:02 ` [PATCH v14 14/19] trace-cmd: Add guest information in host's trace.dat file Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 15/19] trace-cmd: Add host trace clock as guest trace argument Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 16/19] trace-cmd: Refactor few trace-cmd internal functions Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 17/19] trace-cmd: Basic infrastructure for host - guest timestamp synchronization Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 18/19] trace-cmd: [POC] PTP-like algorithm " Tzvetomir Stoyanov (VMware)
2019-11-27 14:02 ` [PATCH v14 19/19] trace-cmd: Debug scripts for " Tzvetomir Stoyanov (VMware)
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