2 * Copyright (C) 2013 Stefan Sauer <ensonic@users.sf.net>
4 * gstlatency.c: tracing module that logs processing latency stats
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
22 * SECTION:element-latencytracer
23 * @short_description: log processing latency stats
25 * A tracing module that determines src-to-sink latencies by injecting custom
26 * events at sources and process them at sinks. This elements supports tracing
27 * the entire pipeline latency and per element latency. By default, only
28 * pipeline latency is traced. The 'flags' parameter can be used to enabled
32 * GST_TRACERS="latency(flags=pipeline+element)" GST_DEBUG=GST_TRACER:7 ./...
35 /* TODO(ensonic): if there are two sources feeding into a mixer/muxer and later
36 * we fan-out with tee and have two sinks, each sink would get all two events,
37 * the later event would overwrite the former. Unfortunately when the buffer
38 * arrives on the sink we don't know to which event it correlates. Better would
39 * be to use the buffer meta in 1.0 instead of the event. Or we track a min/max
47 #include "gstlatency.h"
49 GST_DEBUG_CATEGORY_STATIC (gst_latency_debug);
50 #define GST_CAT_DEFAULT gst_latency_debug
53 GST_DEBUG_CATEGORY_INIT (gst_latency_debug, "latency", 0, "latency tracer");
54 #define gst_latency_tracer_parent_class parent_class
55 G_DEFINE_TYPE_WITH_CODE (GstLatencyTracer, gst_latency_tracer, GST_TYPE_TRACER,
58 static void latency_query_stack_destroy (gpointer data);
60 static GQuark latency_probe_id;
61 static GQuark sub_latency_probe_id;
62 static GQuark latency_probe_pad;
63 static GQuark latency_probe_ts;
64 static GQuark drop_sub_latency_quark;
66 static GstTracerRecord *tr_latency;
67 static GstTracerRecord *tr_element_latency;
68 static GstTracerRecord *tr_element_reported_latency;
70 /* The private stack for each thread */
71 static GPrivate latency_query_stack =
72 G_PRIVATE_INIT (latency_query_stack_destroy);
74 struct LatencyQueryTableValue
76 GstElement *peer_element;
84 * Get the element/bin owning the pad.
90 * out: the element that contains the peer of the proxy
93 * out: the bin owning the ghostpad
95 /* TODO(ensonic): gst_pad_get_parent_element() would not work here, should we
96 * add this as new api, e.g. gst_pad_find_parent_element();
99 get_real_pad_parent (GstPad * pad)
106 parent = GST_OBJECT_PARENT (pad);
108 /* if parent of pad is a ghost-pad, then pad is a proxy_pad */
109 if (parent && GST_IS_GHOST_PAD (parent)) {
110 pad = GST_PAD_CAST (parent);
111 parent = GST_OBJECT_PARENT (pad);
113 return GST_ELEMENT_CAST (parent);
117 latency_query_table_value_destroy (gpointer data)
119 struct LatencyQueryTableValue *v = data;
121 /* Unref the element */
122 if (v->peer_element) {
123 gst_object_unref (v->peer_element);
124 v->peer_element = NULL;
127 /* Destroy the structure */
132 latency_query_stack_destroy (gpointer data)
134 GQueue *queue = data;
135 g_queue_free_full (queue, latency_query_table_value_destroy);
139 local_latency_query_stack_get (void)
141 /* Make sure the stack exists */
142 GQueue *stack = g_private_get (&latency_query_stack);
144 g_private_set (&latency_query_stack, g_queue_new ());
145 stack = g_private_get (&latency_query_stack);
152 static struct LatencyQueryTableValue *
153 local_latency_query_stack_pop (void)
155 GQueue *stack = local_latency_query_stack_get ();
156 return g_queue_pop_tail (stack);
160 local_latency_query_stack_push (struct LatencyQueryTableValue *value)
162 GQueue *stack = local_latency_query_stack_get ();
163 g_queue_push_tail (stack, value);
169 log_latency (const GstStructure * data, GstPad * sink_pad, guint64 sink_ts)
176 value = gst_structure_id_get_value (data, latency_probe_ts);
177 src_ts = g_value_get_uint64 (value);
179 value = gst_structure_id_get_value (data, latency_probe_pad);
180 src = g_value_get_string (value);
182 sink = g_strdup_printf ("%s_%s",
183 GST_DEBUG_PAD_NAME (GST_PAD_PEER (sink_pad)));
184 gst_tracer_record_log (tr_latency, src, sink,
185 GST_CLOCK_DIFF (src_ts, sink_ts), sink_ts);
190 log_element_latency (const GstStructure * data, GstPad * pad, guint64 sink_ts)
196 pad_name = g_strdup_printf ("%s_%s", GST_DEBUG_PAD_NAME (pad));
200 value = gst_structure_id_get_value (data, latency_probe_ts);
201 src_ts = g_value_get_uint64 (value);
203 gst_tracer_record_log (tr_element_latency, pad_name,
204 GST_CLOCK_DIFF (src_ts, sink_ts), sink_ts);
210 send_latency_probe (GstLatencyTracer * self, GstElement * parent, GstPad * pad,
213 GstPad *peer_pad = GST_PAD_PEER (pad);
215 /* allow for non-parented pads to send latency probes as used in e.g.
216 * rtspsrc for TCP connections */
217 if (peer_pad && (!parent || (!GST_IS_BIN (parent)))) {
219 GstEvent *latency_probe;
221 if (self->flags & GST_LATENCY_TRACER_FLAG_PIPELINE &&
222 GST_OBJECT_FLAG_IS_SET (parent, GST_ELEMENT_FLAG_SOURCE)) {
223 pad_name = g_strdup_printf ("%s_%s", GST_DEBUG_PAD_NAME (pad));
225 GST_DEBUG ("%s: Sending latency event", pad_name);
227 latency_probe = gst_event_new_custom (GST_EVENT_CUSTOM_DOWNSTREAM,
228 gst_structure_new_id (latency_probe_id,
229 latency_probe_pad, G_TYPE_STRING, pad_name,
230 latency_probe_ts, G_TYPE_UINT64, ts, NULL));
232 gst_pad_push_event (pad, latency_probe);
235 if (self->flags & GST_LATENCY_TRACER_FLAG_ELEMENT) {
236 GST_DEBUG ("%s_%s: Sending sub-latency event", GST_DEBUG_PAD_NAME (pad));
238 pad_name = g_strdup_printf ("%s_%s", GST_DEBUG_PAD_NAME (peer_pad));
239 latency_probe = gst_event_new_custom (GST_EVENT_CUSTOM_DOWNSTREAM,
240 gst_structure_new_id (sub_latency_probe_id,
241 latency_probe_pad, G_TYPE_STRING, pad_name,
242 latency_probe_ts, G_TYPE_UINT64, ts, NULL));
243 gst_pad_push_event (pad, latency_probe);
250 calculate_latency (GstElement * parent, GstPad * pad, guint64 ts)
252 GstElement *peer_parent = get_real_pad_parent (GST_PAD_PEER (pad));
254 if (parent && (!GST_IS_BIN (parent)) &&
255 (!GST_OBJECT_FLAG_IS_SET (parent, GST_ELEMENT_FLAG_SOURCE))) {
258 /* FIXME unsafe use of peer */
259 if (GST_OBJECT_FLAG_IS_SET (peer_parent, GST_ELEMENT_FLAG_SINK)) {
260 GST_DEBUG ("%s_%s: Should log full lantency now",
261 GST_DEBUG_PAD_NAME (pad));
262 ev = g_object_get_qdata ((GObject *) pad, latency_probe_id);
264 g_object_set_qdata ((GObject *) pad, latency_probe_id, NULL);
265 log_latency (gst_event_get_structure (ev), pad, ts);
266 gst_event_unref (ev);
270 GST_DEBUG ("%s_%s: Should log sub lantency now", GST_DEBUG_PAD_NAME (pad));
271 ev = g_object_get_qdata ((GObject *) pad, sub_latency_probe_id);
273 g_object_set_qdata ((GObject *) pad, sub_latency_probe_id, NULL);
274 log_element_latency (gst_event_get_structure (ev), pad, ts);
275 gst_event_unref (ev);
281 do_push_buffer_pre (GstTracer * tracer, guint64 ts, GstPad * pad)
283 GstLatencyTracer *self = (GstLatencyTracer *) tracer;
284 GstElement *parent = get_real_pad_parent (pad);
286 send_latency_probe (self, parent, pad, ts);
287 calculate_latency (parent, pad, ts);
291 do_pull_range_pre (GstTracer * tracer, guint64 ts, GstPad * pad)
293 GstLatencyTracer *self = (GstLatencyTracer *) tracer;
294 GstPad *peer_pad = GST_PAD_PEER (pad);
295 GstElement *parent = get_real_pad_parent (peer_pad);
297 send_latency_probe (self, parent, peer_pad, ts);
301 do_pull_range_post (GstTracer * self, guint64 ts, GstPad * pad)
303 GstElement *parent = get_real_pad_parent (pad);
305 calculate_latency (parent, pad, ts);
308 static GstPadProbeReturn
309 do_drop_sub_latency_event (GstPad * pad, GstPadProbeInfo * info,
312 GstEvent *ev = info->data;
313 GstPadProbeReturn ret = GST_PAD_PROBE_OK;
315 if (GST_EVENT_TYPE (ev) == GST_EVENT_CUSTOM_DOWNSTREAM) {
316 const GstStructure *data = gst_event_get_structure (ev);
318 if (gst_structure_get_name_id (data) == sub_latency_probe_id) {
320 /* FIXME unsafe peer pad usage */
321 gchar *pad_name = g_strdup_printf ("%s_%s",
322 GST_DEBUG_PAD_NAME (GST_PAD_PEER (pad)));
324 value = gst_structure_id_get_value (data, latency_probe_pad);
325 if (!g_str_equal (g_value_get_string (value), pad_name)) {
326 GST_DEBUG ("%s: Dropping sub-latency event", pad_name);
327 ret = GST_PAD_PROBE_DROP;
338 do_push_event_pre (GstTracer * self, guint64 ts, GstPad * pad, GstEvent * ev)
340 GstElement *parent = get_real_pad_parent (pad);
341 GstPad *peer_pad = GST_PAD_PEER (pad);
342 GstElement *peer_parent = get_real_pad_parent (peer_pad);
344 if (parent && (!GST_IS_BIN (parent)) &&
345 (!GST_OBJECT_FLAG_IS_SET (parent, GST_ELEMENT_FLAG_SOURCE)) &&
346 GST_EVENT_TYPE (ev) == GST_EVENT_CUSTOM_DOWNSTREAM) {
347 const GstStructure *data = gst_event_get_structure (ev);
349 /* if not set yet, add a pad probe that prevents sub-latency event from
351 if (gst_structure_get_name_id (data) == latency_probe_id) {
353 if (!g_object_get_qdata ((GObject *) pad, drop_sub_latency_quark)) {
354 GST_DEBUG ("%s_%s: Adding pad probe to drop sub-latency event",
355 GST_DEBUG_PAD_NAME (pad));
356 gst_pad_add_probe (pad, GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM,
357 do_drop_sub_latency_event, NULL, NULL);
358 g_object_set_qdata ((GObject *) pad, drop_sub_latency_quark,
362 /* FIXME unsafe peer access */
363 if (GST_OBJECT_FLAG_IS_SET (peer_parent, GST_ELEMENT_FLAG_SINK)) {
364 GST_DEBUG ("%s_%s: Storing latency event", GST_DEBUG_PAD_NAME (pad));
366 /* store event so that we can calculate latency when the buffer that
367 * follows has been processed */
368 if (!g_object_get_qdata ((GObject *) pad, latency_probe_id))
369 g_object_set_qdata ((GObject *) pad, latency_probe_id,
374 if (gst_structure_get_name_id (data) == sub_latency_probe_id) {
376 gchar *pad_name = g_strdup_printf ("%s_%s",
377 GST_DEBUG_PAD_NAME (peer_pad));
379 value = gst_structure_id_get_value (data, latency_probe_pad);
381 if (!g_str_equal (g_value_get_string (value), pad_name)) {
382 GST_DEBUG ("%s: Storing sub-latency event", pad_name);
383 if (!g_object_get_qdata ((GObject *) pad, sub_latency_probe_id))
384 g_object_set_qdata ((GObject *) pad, sub_latency_probe_id,
394 do_query_post (GstLatencyTracer * tracer, GstClockTime ts, GstPad * pad,
395 GstQuery * query, gboolean res)
397 /* Only check for latency queries if flag is enabled */
398 if ((tracer->flags & GST_LATENCY_TRACER_FLAG_REPORTED_ELEMENT) &&
399 (GST_QUERY_TYPE (query) == GST_QUERY_LATENCY)) {
401 guint64 min = 0, max = 0, min_prev = 0, max_prev = 0;
403 struct LatencyQueryTableValue *value;
404 GstElement *element = get_real_pad_parent (pad);
405 GstElement *peer_element = get_real_pad_parent (GST_PAD_PEER (pad));
407 /* Parse the query */
408 gst_query_parse_latency (query, &live, &min, &max);
411 value = local_latency_query_stack_pop ();
412 while (value && value->peer_element == element) {
413 min_prev = MAX (value->min, min_prev);
414 max_prev = MAX (value->max, max_prev);
415 value = local_latency_query_stack_pop ();
419 value = g_new0 (struct LatencyQueryTableValue, 1);
420 value->peer_element = gst_object_ref (peer_element);
423 local_latency_query_stack_push (value);
425 /* Get the pad name */
426 element_name = gst_element_get_name (element);
428 /* Log reported latency */
429 gst_tracer_record_log (tr_element_reported_latency, element_name, live,
430 GST_CLOCK_DIFF (min_prev, min), GST_CLOCK_DIFF (max_prev, max), ts);
433 g_free (element_name);
440 gst_latency_tracer_constructed (GObject * object)
442 GstLatencyTracer *self = GST_LATENCY_TRACER (object);
444 GstStructure *params_struct = NULL;
446 g_object_get (self, "params", ¶ms, NULL);
451 tmp = g_strdup_printf ("latency,%s", params);
452 params_struct = gst_structure_from_string (tmp, NULL);
455 /* Read the flags if available */
457 const gchar *flags = gst_structure_get_string (params_struct, "flags");
462 GStrv split = g_strsplit (flags, "+", -1);
465 for (i = 0; split[i]; i++) {
466 if (g_str_equal (split[i], "pipeline"))
467 self->flags |= GST_LATENCY_TRACER_FLAG_PIPELINE;
468 else if (g_str_equal (split[i], "element"))
469 self->flags |= GST_LATENCY_TRACER_FLAG_ELEMENT;
470 else if (g_str_equal (split[i], "reported"))
471 self->flags |= GST_LATENCY_TRACER_FLAG_REPORTED_ELEMENT;
473 GST_WARNING ("Invalid latency tracer flags %s", split[i]);
484 gst_latency_tracer_class_init (GstLatencyTracerClass * klass)
486 GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
488 gobject_class->constructed = gst_latency_tracer_constructed;
490 latency_probe_id = g_quark_from_static_string ("latency_probe.id");
491 sub_latency_probe_id = g_quark_from_static_string ("sub_latency_probe.id");
492 latency_probe_pad = g_quark_from_static_string ("latency_probe.pad");
493 latency_probe_ts = g_quark_from_static_string ("latency_probe.ts");
494 drop_sub_latency_quark =
495 g_quark_from_static_string ("drop_sub_latency.quark");
497 /* announce trace formats */
499 tr_latency = gst_tracer_record_new ("latency.class",
500 "src", GST_TYPE_STRUCTURE, gst_structure_new ("scope",
501 "type", G_TYPE_GTYPE, G_TYPE_STRING,
502 "related-to", GST_TYPE_TRACER_VALUE_SCOPE, GST_TRACER_VALUE_SCOPE_PAD,
504 "sink", GST_TYPE_STRUCTURE, gst_structure_new ("scope",
505 "type", G_TYPE_GTYPE, G_TYPE_STRING,
506 "related-to", GST_TYPE_TRACER_VALUE_SCOPE, GST_TRACER_VALUE_SCOPE_PAD,
508 "time", GST_TYPE_STRUCTURE, gst_structure_new ("value",
509 "type", G_TYPE_GTYPE, G_TYPE_UINT64,
510 "description", G_TYPE_STRING,
511 "time it took for the buffer to go from src to sink ns",
512 "min", G_TYPE_UINT64, G_GUINT64_CONSTANT (0),
513 "max", G_TYPE_UINT64, G_MAXUINT64,
515 "ts", GST_TYPE_STRUCTURE, gst_structure_new ("value",
516 "type", G_TYPE_GTYPE, G_TYPE_UINT64,
517 "description", G_TYPE_STRING, "ts when the latency has been logged",
518 "min", G_TYPE_UINT64, G_GUINT64_CONSTANT (0),
519 "max", G_TYPE_UINT64, G_MAXUINT64,
523 tr_element_latency = gst_tracer_record_new ("element-latency.class",
524 "src", GST_TYPE_STRUCTURE, gst_structure_new ("scope",
525 "type", G_TYPE_GTYPE, G_TYPE_STRING,
526 "related-to", GST_TYPE_TRACER_VALUE_SCOPE, GST_TRACER_VALUE_SCOPE_PAD,
528 "time", GST_TYPE_STRUCTURE, gst_structure_new ("value",
529 "type", G_TYPE_GTYPE, G_TYPE_UINT64,
530 "description", G_TYPE_STRING,
531 "time it took for the buffer to go from src to sink ns",
532 "min", G_TYPE_UINT64, G_GUINT64_CONSTANT (0),
533 "max", G_TYPE_UINT64, G_MAXUINT64,
535 "ts", GST_TYPE_STRUCTURE, gst_structure_new ("value",
536 "type", G_TYPE_GTYPE, G_TYPE_UINT64,
537 "description", G_TYPE_STRING, "ts when the latency has been logged",
538 "min", G_TYPE_UINT64, G_GUINT64_CONSTANT (0),
539 "max", G_TYPE_UINT64, G_MAXUINT64,
544 tr_element_reported_latency = gst_tracer_record_new (
545 "element-reported-latency.class",
546 "element", GST_TYPE_STRUCTURE, gst_structure_new ("scope",
547 "type", G_TYPE_GTYPE, G_TYPE_STRING,
548 "related-to", GST_TYPE_TRACER_VALUE_SCOPE,
549 GST_TRACER_VALUE_SCOPE_ELEMENT,
551 "live", GST_TYPE_STRUCTURE, gst_structure_new ("value",
552 "type", G_TYPE_GTYPE, G_TYPE_BOOLEAN,
553 "description", G_TYPE_STRING,
554 "wether the it is a live stream or not",
556 "min", GST_TYPE_STRUCTURE, gst_structure_new ("value",
557 "type", G_TYPE_GTYPE, G_TYPE_UINT64,
558 "description", G_TYPE_STRING,
559 "the minimum reported latency",
560 "min", G_TYPE_UINT64, G_GUINT64_CONSTANT (0),
561 "max", G_TYPE_UINT64, G_MAXUINT64,
563 "max", GST_TYPE_STRUCTURE, gst_structure_new ("value",
564 "type", G_TYPE_GTYPE, G_TYPE_UINT64,
565 "description", G_TYPE_STRING, "the maximum reported latency",
566 "min", G_TYPE_UINT64, G_GUINT64_CONSTANT (0),
567 "max", G_TYPE_UINT64, G_MAXUINT64,
569 "ts", GST_TYPE_STRUCTURE, gst_structure_new ("value",
570 "type", G_TYPE_GTYPE, G_TYPE_UINT64,
571 "description", G_TYPE_STRING, "ts when the latency has been reported",
572 "min", G_TYPE_UINT64, G_GUINT64_CONSTANT (0),
573 "max", G_TYPE_UINT64, G_MAXUINT64,
580 gst_latency_tracer_init (GstLatencyTracer * self)
582 GstTracer *tracer = GST_TRACER (self);
584 /* only trace pipeline latency by default */
585 self->flags = GST_LATENCY_TRACER_FLAG_PIPELINE;
587 /* in push mode, pre/post will be called before/after the peer chain
588 * function has been called. For this reaosn, we only use -pre to avoid
589 * accounting for the processing time of the peer element (the sink) */
590 gst_tracing_register_hook (tracer, "pad-push-pre",
591 G_CALLBACK (do_push_buffer_pre));
592 gst_tracing_register_hook (tracer, "pad-push-list-pre",
593 G_CALLBACK (do_push_buffer_pre));
595 /* while in pull mode, pre/post will happen before and after the upstream
596 * pull_range call is made, so it already only account for the upstream
597 * processing time. As a side effect, in pull mode, we can measure the
598 * source processing latency, while in push mode, we can't */
599 gst_tracing_register_hook (tracer, "pad-pull-range-pre",
600 G_CALLBACK (do_pull_range_pre));
601 gst_tracing_register_hook (tracer, "pad-pull-range-post",
602 G_CALLBACK (do_pull_range_post));
604 gst_tracing_register_hook (tracer, "pad-push-event-pre",
605 G_CALLBACK (do_push_event_pre));
607 /* Add pad query post hook to get the reported per-element latency */
608 gst_tracing_register_hook (tracer, "pad-query-post",
609 G_CALLBACK (do_query_post));