Trace stats in RTCStatsCollector.

webrtc/pc/rtcstatscollector.cc

 /*
  *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/pc/rtcstatscollector.h"
 
 #include <memory>
 #include <sstream>
 #include <utility>
 #include <vector>
 
 #include "webrtc/api/mediastreaminterface.h"
 #include "webrtc/api/peerconnectioninterface.h"
 #include "webrtc/media/base/mediachannel.h"
 #include "webrtc/p2p/base/candidate.h"
 #include "webrtc/p2p/base/p2pconstants.h"
 #include "webrtc/p2p/base/port.h"
 #include "webrtc/pc/peerconnection.h"
 #include "webrtc/pc/webrtcsession.h"
 #include "webrtc/rtc_base/checks.h"
 #include "webrtc/rtc_base/timeutils.h"
+#include "webrtc/rtc_base/trace_event.h"
 
 namespace webrtc {
 
 namespace {
 
 std::string RTCCertificateIDFromFingerprint(const std::string& fingerprint) {
   return "RTCCertificate_" + fingerprint;
 }
 
 std::string RTCCodecStatsIDFromDirectionMediaAndPayload(
@@ skipping 706 matching lines @@
   else
     partial_report_->TakeMembersFrom(partial_report);
   --num_pending_partial_reports_;
   if (!num_pending_partial_reports_) {
     cache_timestamp_us_ = partial_report_timestamp_us_;
     cached_report_ = partial_report_;
     partial_report_ = nullptr;
     channel_name_pairs_.reset();
     track_media_info_map_.reset();
     track_to_id_.clear();
+    for (const RTCStats& stats : *cached_report_) {
+      for (const RTCStatsMemberInterface* member : stats.Members()) {
+        if (member->is_defined()) {
+          TRACE_EVENT_INSTANT2("webrtc_stats", member->name(),
+                               "value", member->ValueToString(),
+                               stats.type(), stats.id());

[hbos, 2017/07/12 11:26:51]

I think stats name might be wrong to have as trace name, because there are a few
cases where the same member name is used inside different stats dictionaries
even though they're not examples of the same thing. (Example: bytesSent is in
RTCSentRTPStreamStats, RTCDataChannelStats, RTCTransportStats and
RTCIceCandidatePairStats). Probably, the dictionary should be the name argument,
and the additional arguments be the sub-dictionary information, from higher
level information to lower level.

TRACE_EVENT_INSTANT2(
  "webrtc_stats",            // category
  stats.type(),              // name
  "id",                      // arg1_name
  stats.id(),                // arg1_value
  member->name(),            // arg2_name
  member->ValueToString());  // arg2_value

Or if "name" should fully identify an example of this particular metric and not
just the dictionary, then this should probably be the way to go:

TRACE_EVENT_INSTANT2(
  "webrtc_stats",            // category
  stats.type() + "." + member->name(),  // name
  "id",                      // arg1_name
  stats.id(),                // arg1_value
  "value",                   // arg2_name
  member->ValueToString());  // arg2_value

[ehmaldonado_webrtc, 2017/07/12 12:45:51]

Right. Done.

+        }
+      }
+    }
     DeliverCachedReport();
   }
 }
 
 void RTCStatsCollector::DeliverCachedReport() {
   RTC_DCHECK(signaling_thread_->IsCurrent());
   RTC_DCHECK(!callbacks_.empty());
   RTC_DCHECK(cached_report_);
   for (const rtc::scoped_refptr<RTCStatsCollectorCallback>& callback :
        callbacks_) {
@@ skipping 484 matching lines @@
     const std::string& type) {
   return CandidateTypeToRTCIceCandidateType(type);
 }
 
 const char* DataStateToRTCDataChannelStateForTesting(
     DataChannelInterface::DataState state) {
   return DataStateToRTCDataChannelState(state);
 }
 
 }  // namespace webrtc