Track UMA stats for when the renderer side audio device wasn't ready.

content/browser/renderer_host/media/audio_sync_reader.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/media/audio_sync_reader.h"
 
 #include <algorithm>
 
+#include "base/metrics/histogram.h"
 #include "base/process_util.h"
 #include "base/shared_memory.h"
 #include "media/audio/audio_buffers_state.h"
 #include "media/audio/audio_parameters.h"
 #include "media/audio/shared_memory_util.h"
 
 using media::AudioBus;
 
 namespace content {
 
 AudioSyncReader::AudioSyncReader(base::SharedMemory* shared_memory,
                                  const media::AudioParameters& params,
                                  int input_channels)
     : shared_memory_(shared_memory),
-      input_channels_(input_channels) {
+      input_channels_(input_channels),
+      renderer_callback_count_(0),
+      renderer_missed_callback_count_(0) {
   packet_size_ = media::PacketSizeInBytes(shared_memory_->created_size());
   int input_memory_size = 0;
   int output_memory_size = AudioBus::CalculateMemorySize(params);
   if (input_channels_ > 0) {
     // The input storage is after the output storage.
     int frames = params.frames_per_buffer();
     input_memory_size = AudioBus::CalculateMemorySize(input_channels_, frames);
     char* input_data =
         static_cast<char*>(shared_memory_->memory()) + output_memory_size;
     input_bus_ = AudioBus::WrapMemory(input_channels_, frames, input_data);
   }
   DCHECK_EQ(packet_size_, output_memory_size + input_memory_size);
   output_bus_ = AudioBus::WrapMemory(params, shared_memory->memory());
 }
 
 AudioSyncReader::~AudioSyncReader() {
+  if (!renderer_callback_count_)
+    return;
+
+  // Recording the percentage of deadline misses gives us a rough overview of
+  // how many users might be running into audio glitches.
+  int percentage_missed =
+      100.0 * renderer_missed_callback_count_ / renderer_callback_count_;
+  UMA_HISTOGRAM_PERCENTAGE(
+      "Media.AudioRendererMissedDeadline", percentage_missed);
 }
 
 bool AudioSyncReader::DataReady() {
   return !media::IsUnknownDataSize(shared_memory_, packet_size_);
 }
 
 // media::AudioOutputController::SyncReader implementations.
 void AudioSyncReader::UpdatePendingBytes(uint32 bytes) {
   if (bytes != static_cast<uint32>(media::kPauseMark)) {
     // Store unknown length of data into buffer, so we later
     // can find out if data became available.
     media::SetUnknownDataSize(shared_memory_, packet_size_);
   }
 
   if (socket_.get()) {
     socket_->Send(&bytes, sizeof(bytes));
   }
 }
 
 int AudioSyncReader::Read(AudioBus* source, AudioBus* dest) {
+  ++renderer_callback_count_;
+  if (!DataReady())
+    ++renderer_missed_callback_count_;
+
   // Copy optional synchronized live audio input for consumption by renderer
   // process.
   if (source && input_bus_.get()) {
     DCHECK_EQ(source->channels(), input_bus_->channels());
     DCHECK_LE(source->frames(), input_bus_->frames());
     source->CopyTo(input_bus_.get());
   }
 
   // Retrieve the actual number of bytes available from the shared memory.  If
   // the renderer has not completed rendering this value will be invalid (still
@@ skipping 62 matching lines @@
     base::FileDescriptor* foreign_handle) {
   foreign_handle->fd = foreign_socket_->handle();
   foreign_handle->auto_close = false;
   if (foreign_handle->fd != -1)
     return true;
   return false;
 }
 #endif
 
 }  // namespace content