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 GQuark latency_probe_id;
59 static GQuark sub_latency_probe_id;
60 static GQuark latency_probe_pad;
61 static GQuark latency_probe_ts;
62 static GQuark drop_sub_latency_quark;
64 static GstTracerRecord *tr_latency;
65 static GstTracerRecord *tr_element_latency;
70 * Get the element/bin owning the pad.
76 * out: the element that contains the peer of the proxy
79 * out: the bin owning the ghostpad
81 /* TODO(ensonic): gst_pad_get_parent_element() would not work here, should we
82 * add this as new api, e.g. gst_pad_find_parent_element();
85 get_real_pad_parent (GstPad * pad)
92 parent = GST_OBJECT_PARENT (pad);
94 /* if parent of pad is a ghost-pad, then pad is a proxy_pad */
95 if (parent && GST_IS_GHOST_PAD (parent)) {
96 pad = GST_PAD_CAST (parent);
97 parent = GST_OBJECT_PARENT (pad);
99 return GST_ELEMENT_CAST (parent);
105 log_latency (const GstStructure * data, GstPad * sink_pad, guint64 sink_ts)
112 value = gst_structure_id_get_value (data, latency_probe_ts);
113 src_ts = g_value_get_uint64 (value);
115 value = gst_structure_id_get_value (data, latency_probe_pad);
116 src = g_value_get_string (value);
118 sink = g_strdup_printf ("%s_%s",
119 GST_DEBUG_PAD_NAME (GST_PAD_PEER (sink_pad)));
120 gst_tracer_record_log (tr_latency, src, sink,
121 GST_CLOCK_DIFF (src_ts, sink_ts), sink_ts);
126 log_element_latency (const GstStructure * data, GstPad * pad, guint64 sink_ts)
132 pad_name = g_strdup_printf ("%s_%s", GST_DEBUG_PAD_NAME (pad));
136 value = gst_structure_id_get_value (data, latency_probe_ts);
137 src_ts = g_value_get_uint64 (value);
139 gst_tracer_record_log (tr_element_latency, pad_name,
140 GST_CLOCK_DIFF (src_ts, sink_ts), sink_ts);
146 send_latency_probe (GstLatencyTracer * self, GstElement * parent, GstPad * pad,
149 GstPad *peer_pad = GST_PAD_PEER (pad);
151 /* allow for non-parented pads to send latency probes as used in e.g.
152 * rtspsrc for TCP connections */
153 if (peer_pad && (!parent || (!GST_IS_BIN (parent)))) {
155 GstEvent *latency_probe;
157 if (self->flags & GST_LATENCY_TRACER_FLAG_PIPELINE &&
158 GST_OBJECT_FLAG_IS_SET (parent, GST_ELEMENT_FLAG_SOURCE)) {
159 pad_name = g_strdup_printf ("%s_%s", GST_DEBUG_PAD_NAME (pad));
161 GST_DEBUG ("%s: Sending latency event", pad_name);
163 latency_probe = gst_event_new_custom (GST_EVENT_CUSTOM_DOWNSTREAM,
164 gst_structure_new_id (latency_probe_id,
165 latency_probe_pad, G_TYPE_STRING, pad_name,
166 latency_probe_ts, G_TYPE_UINT64, ts, NULL));
168 gst_pad_push_event (pad, latency_probe);
171 if (self->flags & GST_LATENCY_TRACER_FLAG_ELEMENT) {
172 GST_DEBUG ("%s_%s: Sending sub-latency event", GST_DEBUG_PAD_NAME (pad));
174 pad_name = g_strdup_printf ("%s_%s", GST_DEBUG_PAD_NAME (peer_pad));
175 latency_probe = gst_event_new_custom (GST_EVENT_CUSTOM_DOWNSTREAM,
176 gst_structure_new_id (sub_latency_probe_id,
177 latency_probe_pad, G_TYPE_STRING, pad_name,
178 latency_probe_ts, G_TYPE_UINT64, ts, NULL));
179 gst_pad_push_event (pad, latency_probe);
186 calculate_latency (GstElement * parent, GstPad * pad, guint64 ts)
188 GstElement *peer_parent = get_real_pad_parent (GST_PAD_PEER (pad));
190 if (parent && (!GST_IS_BIN (parent)) &&
191 (!GST_OBJECT_FLAG_IS_SET (parent, GST_ELEMENT_FLAG_SOURCE))) {
194 /* FIXME unsafe use of peer */
195 if (GST_OBJECT_FLAG_IS_SET (peer_parent, GST_ELEMENT_FLAG_SINK)) {
196 GST_DEBUG ("%s_%s: Should log full lantency now",
197 GST_DEBUG_PAD_NAME (pad));
198 ev = g_object_get_qdata ((GObject *) pad, latency_probe_id);
200 g_object_set_qdata ((GObject *) pad, latency_probe_id, NULL);
201 log_latency (gst_event_get_structure (ev), pad, ts);
202 gst_event_unref (ev);
206 GST_DEBUG ("%s_%s: Should log sub lantency now", GST_DEBUG_PAD_NAME (pad));
207 ev = g_object_get_qdata ((GObject *) pad, sub_latency_probe_id);
209 g_object_set_qdata ((GObject *) pad, sub_latency_probe_id, NULL);
210 log_element_latency (gst_event_get_structure (ev), pad, ts);
211 gst_event_unref (ev);
217 do_push_buffer_pre (GstTracer * tracer, guint64 ts, GstPad * pad)
219 GstLatencyTracer *self = (GstLatencyTracer *) tracer;
220 GstElement *parent = get_real_pad_parent (pad);
222 send_latency_probe (self, parent, pad, ts);
223 calculate_latency (parent, pad, ts);
227 do_pull_range_pre (GstTracer * tracer, guint64 ts, GstPad * pad)
229 GstLatencyTracer *self = (GstLatencyTracer *) tracer;
230 GstPad *peer_pad = GST_PAD_PEER (pad);
231 GstElement *parent = get_real_pad_parent (peer_pad);
233 send_latency_probe (self, parent, peer_pad, ts);
237 do_pull_range_post (GstTracer * self, guint64 ts, GstPad * pad)
239 GstElement *parent = get_real_pad_parent (pad);
241 calculate_latency (parent, pad, ts);
244 static GstPadProbeReturn
245 do_drop_sub_latency_event (GstPad * pad, GstPadProbeInfo * info,
248 GstEvent *ev = info->data;
249 GstPadProbeReturn ret = GST_PAD_PROBE_OK;
251 if (GST_EVENT_TYPE (ev) == GST_EVENT_CUSTOM_DOWNSTREAM) {
252 const GstStructure *data = gst_event_get_structure (ev);
254 if (gst_structure_get_name_id (data) == sub_latency_probe_id) {
256 /* FIXME unsafe peer pad usage */
257 gchar *pad_name = g_strdup_printf ("%s_%s",
258 GST_DEBUG_PAD_NAME (GST_PAD_PEER (pad)));
260 value = gst_structure_id_get_value (data, latency_probe_pad);
261 if (!g_str_equal (g_value_get_string (value), pad_name)) {
262 GST_DEBUG ("%s: Dropping sub-latency event", pad_name);
263 ret = GST_PAD_PROBE_DROP;
274 do_push_event_pre (GstTracer * self, guint64 ts, GstPad * pad, GstEvent * ev)
276 GstElement *parent = get_real_pad_parent (pad);
277 GstPad *peer_pad = GST_PAD_PEER (pad);
278 GstElement *peer_parent = get_real_pad_parent (peer_pad);
280 if (parent && (!GST_IS_BIN (parent)) &&
281 (!GST_OBJECT_FLAG_IS_SET (parent, GST_ELEMENT_FLAG_SOURCE)) &&
282 GST_EVENT_TYPE (ev) == GST_EVENT_CUSTOM_DOWNSTREAM) {
283 const GstStructure *data = gst_event_get_structure (ev);
285 /* if not set yet, add a pad probe that prevents sub-latency event from
287 if (gst_structure_get_name_id (data) == latency_probe_id) {
289 if (!g_object_get_qdata ((GObject *) pad, drop_sub_latency_quark)) {
290 GST_DEBUG ("%s_%s: Adding pad probe to drop sub-latency event",
291 GST_DEBUG_PAD_NAME (pad));
292 gst_pad_add_probe (pad, GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM,
293 do_drop_sub_latency_event, NULL, NULL);
294 g_object_set_qdata ((GObject *) pad, drop_sub_latency_quark,
298 /* FIXME unsafe peer access */
299 if (GST_OBJECT_FLAG_IS_SET (peer_parent, GST_ELEMENT_FLAG_SINK)) {
300 GST_DEBUG ("%s_%s: Storing latency event", GST_DEBUG_PAD_NAME (pad));
302 /* store event so that we can calculate latency when the buffer that
303 * follows has been processed */
304 if (!g_object_get_qdata ((GObject *) pad, latency_probe_id))
305 g_object_set_qdata ((GObject *) pad, latency_probe_id,
310 if (gst_structure_get_name_id (data) == sub_latency_probe_id) {
312 gchar *pad_name = g_strdup_printf ("%s_%s",
313 GST_DEBUG_PAD_NAME (peer_pad));
315 value = gst_structure_id_get_value (data, latency_probe_pad);
317 if (!g_str_equal (g_value_get_string (value), pad_name)) {
318 GST_DEBUG ("%s: Storing sub-latency event", pad_name);
319 if (!g_object_get_qdata ((GObject *) pad, sub_latency_probe_id))
320 g_object_set_qdata ((GObject *) pad, sub_latency_probe_id,
332 gst_latency_tracer_constructed (GObject * object)
334 GstLatencyTracer *self = GST_LATENCY_TRACER (object);
336 GstStructure *params_struct = NULL;
338 g_object_get (self, "params", ¶ms, NULL);
343 tmp = g_strdup_printf ("latency,%s", params);
344 params_struct = gst_structure_from_string (tmp, NULL);
347 /* Read the flags if available */
349 const gchar *flags = gst_structure_get_string (params_struct, "flags");
354 GStrv split = g_strsplit (flags, "+", -1);
357 for (i = 0; split[i]; i++) {
358 if (g_str_equal (split[i], "pipeline"))
359 self->flags |= GST_LATENCY_TRACER_FLAG_PIPELINE;
360 else if (g_str_equal (split[i], "element"))
361 self->flags |= GST_LATENCY_TRACER_FLAG_ELEMENT;
363 GST_WARNING ("Invalid latency tracer flags %s", split[i]);
374 gst_latency_tracer_class_init (GstLatencyTracerClass * klass)
376 GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
378 gobject_class->constructed = gst_latency_tracer_constructed;
380 latency_probe_id = g_quark_from_static_string ("latency_probe.id");
381 sub_latency_probe_id = g_quark_from_static_string ("sub_latency_probe.id");
382 latency_probe_pad = g_quark_from_static_string ("latency_probe.pad");
383 latency_probe_ts = g_quark_from_static_string ("latency_probe.ts");
384 drop_sub_latency_quark =
385 g_quark_from_static_string ("drop_sub_latency.quark");
387 /* announce trace formats */
389 tr_latency = gst_tracer_record_new ("latency.class",
390 "src", GST_TYPE_STRUCTURE, gst_structure_new ("scope",
391 "type", G_TYPE_GTYPE, G_TYPE_STRING,
392 "related-to", GST_TYPE_TRACER_VALUE_SCOPE, GST_TRACER_VALUE_SCOPE_PAD,
394 "sink", GST_TYPE_STRUCTURE, gst_structure_new ("scope",
395 "type", G_TYPE_GTYPE, G_TYPE_STRING,
396 "related-to", GST_TYPE_TRACER_VALUE_SCOPE, GST_TRACER_VALUE_SCOPE_PAD,
398 "time", GST_TYPE_STRUCTURE, gst_structure_new ("value",
399 "type", G_TYPE_GTYPE, G_TYPE_UINT64,
400 "description", G_TYPE_STRING,
401 "time it took for the buffer to go from src to sink ns",
402 "min", G_TYPE_UINT64, G_GUINT64_CONSTANT (0),
403 "max", G_TYPE_UINT64, G_MAXUINT64,
405 "ts", GST_TYPE_STRUCTURE, gst_structure_new ("value",
406 "type", G_TYPE_GTYPE, G_TYPE_UINT64,
407 "description", G_TYPE_STRING, "ts when the latency has been logged",
408 "min", G_TYPE_UINT64, G_GUINT64_CONSTANT (0),
409 "max", G_TYPE_UINT64, G_MAXUINT64,
413 tr_element_latency = gst_tracer_record_new ("element-latency.class",
414 "src", GST_TYPE_STRUCTURE, gst_structure_new ("scope",
415 "type", G_TYPE_GTYPE, G_TYPE_STRING,
416 "related-to", GST_TYPE_TRACER_VALUE_SCOPE, GST_TRACER_VALUE_SCOPE_PAD,
418 "time", GST_TYPE_STRUCTURE, gst_structure_new ("value",
419 "type", G_TYPE_GTYPE, G_TYPE_UINT64,
420 "description", G_TYPE_STRING,
421 "time it took for the buffer to go from src to sink ns",
422 "min", G_TYPE_UINT64, G_GUINT64_CONSTANT (0),
423 "max", G_TYPE_UINT64, G_MAXUINT64,
425 "ts", GST_TYPE_STRUCTURE, gst_structure_new ("value",
426 "type", G_TYPE_GTYPE, G_TYPE_UINT64,
427 "description", G_TYPE_STRING, "ts when the latency has been logged",
428 "min", G_TYPE_UINT64, G_GUINT64_CONSTANT (0),
429 "max", G_TYPE_UINT64, G_MAXUINT64,
436 gst_latency_tracer_init (GstLatencyTracer * self)
438 GstTracer *tracer = GST_TRACER (self);
440 /* only trace pipeline latency by default */
441 self->flags = GST_LATENCY_TRACER_FLAG_PIPELINE;
443 /* in push mode, pre/post will be called before/after the peer chain
444 * function has been called. For this reaosn, we only use -pre to avoid
445 * accounting for the processing time of the peer element (the sink) */
446 gst_tracing_register_hook (tracer, "pad-push-pre",
447 G_CALLBACK (do_push_buffer_pre));
448 gst_tracing_register_hook (tracer, "pad-push-list-pre",
449 G_CALLBACK (do_push_buffer_pre));
451 /* while in pull mode, pre/post will happen before and after the upstream
452 * pull_range call is made, so it already only account for the upstream
453 * processing time. As a side effect, in pull mode, we can measure the
454 * source processing latency, while in push mode, we can't */
455 gst_tracing_register_hook (tracer, "pad-pull-range-pre",
456 G_CALLBACK (do_pull_range_pre));
457 gst_tracing_register_hook (tracer, "pad-pull-range-post",
458 G_CALLBACK (do_pull_range_post));
460 gst_tracing_register_hook (tracer, "pad-push-event-pre",
461 G_CALLBACK (do_push_event_pre));