[PATCH v23 0/2] Timestamp synchronization of host - guest tracing session

[PATCH v23 0/2] 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. 

[
 v23 changes:
  - Added flags to PTP start message to control the behaviour of the
    algorithm. This is for development purposes mostly, to compare and
    evaluate how these changes affect the accuracy.
	PTP_FLAG_FASTEST_RESPONSE:  Consider only the probe with fastest
				    response time, otherwise make a histogram
				    from all probes.
	PTP_FLAG_USE_MARKER: Use trace marker to get the clock,
 			     otherwise use directly the system clock

 v22 changes, addressed Steven's comments:
  - Fixed error flow in read_qemu_guests_pids(), free allocated resources
    in case of an error.
  - Fixed initialisation of reallocated memmory in set_vcpu_pid_mapping().
  - Fixed bitmask logic in tracecmd_tsync_proto_select().
  - Fixed usage of wrong structure in make_trace_resp().

 v21 changes:
  - Rebased on top of latest master.
  - Remove these two patches from the set, as they are already merged:
       trace-cmd: Add new library API for local CPU count
       trace-cmd: Add support for negative time offsets in trace.dat file
  - Added more descriptive warning message when fails to extract Time Shift
    information from the trace.dat file.
  - Added a warning message when fails to obtain vcpu - pid mappings.
  - Handle the case with sparse VCPU numbers in VCPU - PID mapping
    array.
  - Fixed broken recording over FIFOs.
 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 (VMware) (2):
  trace-cmd: [POC] PTP-like algorithm for host - guest timestamp
    synchronization
  trace-cmd: Debug scripts for PTP-like algorithm for host - guest
    timestamp synchronization

 include/trace-cmd/trace-cmd.h      |   1 +
 lib/trace-cmd/Makefile             |   1 +
 lib/trace-cmd/trace-timesync-ptp.c | 690 +++++++++++++++++++++++++++++
 lib/trace-cmd/trace-timesync.c     |   8 +
 scripts/debug/tsync_hist.py        |  57 +++
 scripts/debug/tsync_readme         |  12 +
 scripts/debug/tsync_res.py         |  46 ++
 tracecmd/trace-agent.c             |   2 +
 tracecmd/trace-record.c            |  23 +-
 9 files changed, 832 insertions(+), 8 deletions(-)
 create mode 100644 lib/trace-cmd/trace-timesync-ptp.c
 create mode 100644 scripts/debug/tsync_hist.py
 create mode 100644 scripts/debug/tsync_readme
 create mode 100644 scripts/debug/tsync_res.py

-- 
2.25.1

[PATCH v23 1/2] 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 | 690 +++++++++++++++++++++++++++++
 lib/trace-cmd/trace-timesync.c     |   8 +
 tracecmd/trace-agent.c             |   2 +
 tracecmd/trace-record.c            |  23 +-
 6 files changed, 717 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 595919d5..2574edd0 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..19e2f647
--- /dev/null
+++ b/lib/trace-cmd/trace-timesync-ptp.c
@@ -0,0 +1,690 @@
+// 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
+
+/* print time sync debug messages */
+#define TSYNC_DEBUG
+
+struct ptp_clock_sync {
+	struct tep_handle	*tep;
+	int			raw_id;
+	int			marker_fd;
+	int			series_id;
+	int			flags;
+	int			debug_fd;
+};
+
+enum {
+/* Consider only the probe with fastest response time,
+ * otherwise make a histogram from all probes.
+ */
+	PTP_FLAG_FASTEST_RESPONSE		= (1 << 0),
+/* Use trace marker to get the clock,
+ * otherwise use directly the system clock
+ */
+	PTP_FLAG_USE_MARKER			= (1 << 1),
+};
+static int ptp_flags = PTP_FLAG_FASTEST_RESPONSE | PTP_FLAG_USE_MARKER;
+
+struct ptp_clock_start_msg {
+	be32	series_id;
+	be32	flags;
+} __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 void ptp_probe_store(struct ptp_markers_context *ctx,
+			    struct ptp_marker *marker,
+			    unsigned long long ts)
+{
+	int index = -1;
+
+	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 = ts;
+		ctx->msg.count++;
+	}
+}
+
+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;
+
+	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)
+			ptp_probe_store(ctx, marker, record->ts);
+	}
+
+	return 0;
+}
+
+static int ptp_calc_offset_fastest(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;
+}
+
+static int ptp_calc_offset_hist(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;
+}
+
+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 inline void ptp_track_clock(struct ptp_markers_context *ctx,
+				   struct ptp_marker *marker)
+{
+	if (ctx->ptp->flags & PTP_FLAG_USE_MARKER) {
+		write(ctx->ptp->marker_fd, marker, sizeof(struct ptp_marker));
+	} else {
+		struct timespec clock;
+		unsigned long long ts;
+
+		clock_gettime(CLOCK_MONOTONIC_RAW, &clock);
+		ts = clock.tv_sec * 1000000000LL;
+		ts += clock.tv_nsec;
+		ptp_probe_store(ctx, marker, ts);
+	}
+}
+
+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;
+	ptp->flags = ntohl(start.flags);
+	msg = (char *)&count;
+	size = sizeof(count);
+	ctx.msg.count = 0;
+	ctx.size = PTP_SYNC_LOOP;
+	ctx.ptp = ptp;
+	ctx.clock = clock_context;
+	ctx.msg.series_id = ptp->series_id;
+	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);
+		ptp_track_clock(&ctx, &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;
+
+	if (ptp->flags & PTP_FLAG_USE_MARKER)
+		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;
+	ptp->flags = ptp_flags;
+	memset(&start, 0, sizeof(start));
+	start.series_id = htonl(ptp->series_id + 1);
+	start.flags = htonl(ptp->flags);
+	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);
+	ctx.size = 2*PTP_SYNC_LOOP;
+	ctx.ptp = ptp;
+	ctx.clock = clock_context;
+	ctx.msg.count = 0;
+	ctx.msg.series_id = ptp->series_id;
+	do {
+		marker.data.count = count++;
+		marker.data.packet_id = 's';
+		msg_count = htonl(marker.data.count);
+		ptp_track_clock(&ctx, &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';
+		ptp_track_clock(&ctx, &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);
+	if (ptp->flags & PTP_FLAG_USE_MARKER)
+		tracefs_iterate_raw_events(ptp->tep, clock_context->instance,
+					   ptp_marker_find, &ctx);
+	if (ptp->flags & PTP_FLAG_FASTEST_RESPONSE)
+		ptp_calc_offset_fastest(clock_context, &ctx.msg, results, offset,
+					timestamp, &bad_probes);
+	else
+		ptp_calc_offset_hist(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, PTP flags 0x%X\n\r",
+			ptp->series_id, *offset, results->count, bad_probes, ptp->flags);
+		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 35a41394..e294698b 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 c8c853f8..ffc91011 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -6141,10 +6141,6 @@ 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)
 {
@@ -6278,12 +6274,23 @@ 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);
 }
 
@@ -6363,7 +6370,7 @@ 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);
 }
 
@@ -6382,7 +6389,7 @@ 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);
 }
@@ -6401,7 +6408,7 @@ 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);
 }
 
-- 
2.25.1

[PATCH v23 2/2] 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()
-- 
2.25.1