Bug 1006641: add telemetry for AudioStream open times r=jib

content/media/AudioStream.cpp

@@ -13,6 +13,7 @@
 #include "mozilla/Mutex.h"
 #include <algorithm>
 #include "mozilla/Preferences.h"
+#include "mozilla/Telemetry.h"
 #include "soundtouch/SoundTouch.h"
 #include "Latency.h"
 
@@ -72,6 +73,16 @@ bool AudioStream::sCubebLatencyPrefSet;
   }
 }
 
+/*static*/ bool AudioStream::GetFirstStream()
+{
+  static bool sFirstStream = true;
+
+  StaticMutexAutoLock lock(sMutex);
+  bool result = sFirstStream;
+  sFirstStream = false;
+  return result;
+}
+
 /*static*/ double AudioStream::GetVolumeScale()
 {
   StaticMutexAutoLock lock(sMutex);
@@ -384,6 +395,9 @@ AudioStream::Init(int32_t aNumChannels, int32_t aRate,
                   const dom::AudioChannel aAudioChannel,
                   LatencyRequest aLatencyRequest)
 {
+  mStartTime = TimeStamp::Now();
+  mIsFirst = GetFirstStream();
+
   if (!GetCubebContext() || aNumChannels < 0 || aRate < 0) {
     return NS_ERROR_FAILURE;
   }
@@ -494,6 +508,14 @@ AudioStream::OpenCubeb(cubeb_stream_params &aParams,
     }
   }
 
+  if (!mStartTime.IsNull()) {
+		TimeDuration timeDelta = TimeStamp::Now() - mStartTime;
+    LOG(("AudioStream creation time %sfirst: %u ms", mIsFirst ? "" : "not ",
+         (uint32_t) timeDelta.ToMilliseconds()));
+		Telemetry::Accumulate(mIsFirst ? Telemetry::AUDIOSTREAM_FIRST_OPEN_MS :
+                          Telemetry::AUDIOSTREAM_LATER_OPEN_MS, timeDelta.ToMilliseconds());
+  }
+
   return NS_OK;
 }
 

content/media/AudioStream.h

@@ -307,6 +307,7 @@ private:
 
   static void PrefChanged(const char* aPref, void* aClosure);
   static double GetVolumeScale();
+  static bool GetFirstStream();
   static cubeb* GetCubebContext();
   static cubeb* GetCubebContextUnlocked();
   static uint32_t GetCubebLatency();
@@ -423,6 +424,7 @@ private:
 
   StreamState mState;
   bool mNeedsStart; // needed in case Start() is called before cubeb is open
+  bool mIsFirst;
 
   // This mutex protects the static members below.
   static StaticMutex sMutex;

toolkit/components/telemetry/Histograms.json

@@ -50,6 +50,20 @@
     "kind": "boolean",
     "description": "Application reputation query count (both local and remote)"
   },
+  "AUDIOSTREAM_FIRST_OPEN_MS": {
+    "expires_in_version": "never",
+    "kind": "exponential",
+    "high": "10000",
+    "n_buckets": "50",
+    "description": "The length of time (in milliseconds) for the first open of AudioStream."
+  },
+  "AUDIOSTREAM_LATER_OPEN_MS": {
+    "expires_in_version": "never",
+    "kind": "exponential",
+    "high": "10000",
+    "n_buckets": "50",
+    "description": "The length of time (in milliseconds) for the subsequent opens of AudioStream."
+  },
   "BACKGROUNDFILESAVER_THREAD_COUNT": {
     "expires_in_version": "never",
     "kind": "enumerated",