Add UMA histograms for WebAudio

third_party/WebKit/Source/modules/webaudio/OfflineAudioContext.cpp

 /*
  * Copyright (C) 2012, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 17 matching lines @@
 #include "bindings/core/v8/ScriptState.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContext.h"
 #include "modules/webaudio/AudioListener.h"
 #include "modules/webaudio/DeferredTaskHandler.h"
 #include "modules/webaudio/OfflineAudioCompletionEvent.h"
 #include "modules/webaudio/OfflineAudioDestinationNode.h"
 
+#include "platform/Histogram.h"
 #include "platform/audio/AudioUtilities.h"
 
 namespace blink {
 
 OfflineAudioContext* OfflineAudioContext::create(ExecutionContext* context, unsigned numberOfChannels, unsigned numberOfFrames, float sampleRate, ExceptionState& exceptionState)
 {
     // FIXME: add support for workers.
     if (!context || !context->isDocument()) {
         exceptionState.throwDOMException(
             NotSupportedError,
@@ skipping 35 matching lines @@
 
     if (!audioContext->destination()) {
         exceptionState.throwDOMException(
             NotSupportedError,
             "OfflineAudioContext(" + String::number(numberOfChannels)
             + ", " + String::number(numberOfFrames)
             + ", " + String::number(sampleRate)
             + ")");
     }
 
+    DEFINE_STATIC_LOCAL(SparseHistogram, offlineContextChannelCountHistogram,
+        ("WebAudio.OfflineAudioContext.ChannelCount"));
+    DEFINE_STATIC_LOCAL(SparseHistogram, offlineContextLengthHistogram,
+        ("WebAudio.OfflineAudioContext.Length"));
+    DEFINE_STATIC_LOCAL(SparseHistogram, offlineContextSampleRateHistogram,
+        ("WebAudio.OfflineAudioContext.SampleRate"));
+
+    offlineContextChannelCountHistogram.sample(numberOfChannels);
+    // To limit the size of the histogram, record 10*log10(numberOfFrames),
+    // clipping the value at 60 (buffer size of 1 million frames). This
+    // gives 60 entries in the histogram.
+    double histogramValue = 10*log10(numberOfFrames);
+    offlineContextLengthHistogram.sample(clampTo(static_cast<int>(0.5 + histogramValue), 0, 60));
+
+    // To limit the size of the histogram, record
+    // 40+10*log2(sampleRate/48000), clipping the value to lie between 0
+    // and 60.  These limits correspond to a min rate of 3000 and a max of
+    // 192000.  This gives 60 entries in the histogram.
+    histogramValue = 40 + 10*log2(sampleRate / 48000);
+    offlineContextSampleRateHistogram.sample(clampTo(static_cast<int>(0.5 + histogramValue), 0, 60));
+
     audioContext->suspendIfNeeded();
     return audioContext;
 }
 
 OfflineAudioContext::OfflineAudioContext(Document* document, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate, ExceptionState& exceptionState)
     : AbstractAudioContext(document, numberOfChannels, numberOfFrames, sampleRate)
     , m_isRenderingStarted(false)
     , m_totalRenderFrames(numberOfFrames)
 {
     // Create a new destination for offline rendering.
@@ skipping 313 matching lines @@
     // Note that the GraphLock is required before this check. Since this needs
     // to run on the audio thread, OfflineGraphAutoLocker must be used.
     if (m_scheduledSuspends.contains(currentSampleFrame()))
         return true;
 
     return false;
 }
 
 } // namespace blink