Audio input traces for Mac (browser-side)

media/audio/mac/audio_input_mac.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 "media/audio/mac/audio_input_mac.h"
 
 #include <CoreServices/CoreServices.h>
 
 #include "base/logging.h"
 #include "base/mac/mac_logging.h"
+#include "base/trace_event/trace_event.h"
 #include "media/audio/mac/audio_manager_mac.h"
 #include "media/base/audio_bus.h"
 
 namespace media {
 
 PCMQueueInAudioInputStream::PCMQueueInAudioInputStream(
     AudioManagerMac* manager,
     const AudioParameters& params)
     : manager_(manager),
       callback_(NULL),
@@ skipping 174 matching lines @@
 }
 
 void PCMQueueInAudioInputStream::HandleInputBuffer(
     AudioQueueRef audio_queue,
     AudioQueueBufferRef audio_buffer,
     const AudioTimeStamp* start_time,
     UInt32 num_packets,
     const AudioStreamPacketDescription* packet_desc) {
   DCHECK_EQ(audio_queue_, audio_queue);
   DCHECK(audio_buffer->mAudioData);
+  TRACE_EVENT0("audio", "PCMQueueInAudioInputStream::HandleInputBuffer");
   if (!callback_) {
     // This can happen if Stop() was called without start.
     DCHECK_EQ(0U, audio_buffer->mAudioDataByteSize);
     return;
   }
 
   if (audio_buffer->mAudioDataByteSize) {
     // The AudioQueue API may use a large internal buffer and repeatedly call us
     // back to back once that internal buffer is filled.  When this happens the
     // renderer client does not have enough time to read data back from the
     // shared memory before the next write comes along.  If HandleInputBuffer()
     // is called too frequently, Sleep() at least 5ms to ensure the shared
     // memory doesn't get trampled.
     // TODO(dalecurtis): This is a HACK.  Long term the AudioQueue path is going
     // away in favor of the AudioUnit based AUAudioInputStream().  Tracked by
     // http://crbug.com/161383.
     base::TimeDelta elapsed = base::TimeTicks::Now() - last_fill_;
     const base::TimeDelta kMinDelay = base::TimeDelta::FromMilliseconds(5);
-    if (elapsed < kMinDelay)
+    if (elapsed < kMinDelay) {
+      TRACE_EVENT0("audio",
+                   "PCMQueueInAudioInputStream::HandleInputBuffer sleep");
       base::PlatformThread::Sleep(kMinDelay - elapsed);
+    }
 
     uint8_t* audio_data = reinterpret_cast<uint8_t*>(audio_buffer->mAudioData);
     audio_bus_->FromInterleaved(
         audio_data, audio_bus_->frames(), format_.mBitsPerChannel / 8);
     callback_->OnData(
         this, audio_bus_.get(), audio_buffer->mAudioDataByteSize, 0.0);
 
     last_fill_ = base::TimeTicks::Now();
   }
   // Recycle the buffer.
   OSStatus err = QueueNextBuffer(audio_buffer);
   if (err != noErr) {
     if (err == kAudioQueueErr_EnqueueDuringReset) {
       // This is the error you get if you try to enqueue a buffer and the
       // queue has been closed. Not really a problem if indeed the queue
       // has been closed.
       // TODO(joth): PCMQueueOutAudioOutputStream uses callback_ to provide an
       // extra guard for this situation, but it seems to introduce more
       // complications than it solves (memory barrier issues accessing it from
       // multiple threads, looses the means to indicate OnClosed to client).
       // Should determine if we need to do something equivalent here.
       return;
     }
     HandleError(err);
   }
 }
 
 }  // namespace media