aaudio: reduce glitching by improving sleep timing
ALways sleep a minimum time to avoid busy wait in real-time thread.
Account for wakeup jitter in threads on the other side of a FIFO.
Avoid race condition that caused a longer sleep than necessary.
Fix calculation of mFreeRunning for capture mode.
Also added systrace logging, which was used to debug this.
Bug: 63814792
Test: Run GStomper on Walleye with MMAP on, see bug
Change-Id: I7b20098580ff454365425bd21e43c17ade532a0a
diff --git a/media/libaaudio/src/client/AudioStreamInternalPlay.cpp b/media/libaaudio/src/client/AudioStreamInternalPlay.cpp
index 1b18577..31e0a40 100644
--- a/media/libaaudio/src/client/AudioStreamInternalPlay.cpp
+++ b/media/libaaudio/src/client/AudioStreamInternalPlay.cpp
@@ -18,6 +18,10 @@
//#define LOG_NDEBUG 0
#include <utils/Log.h>
+#define ATRACE_TAG ATRACE_TAG_AUDIO
+
+#include <utils/Trace.h>
+
#include "client/AudioStreamInternalPlay.h"
#include "utility/AudioClock.h"
@@ -99,6 +103,10 @@
return result;
}
+ const char *traceName = "aaWrNow";
+ ATRACE_BEGIN(traceName);
+
+ // If a DMA channel or DSP is reading the other end then we have to update the readCounter.
if (mAudioEndpoint.isFreeRunning()) {
// Update data queue based on the timing model.
int64_t estimatedReadCounter = mClockModel.convertTimeToPosition(currentNanoTime);
@@ -108,10 +116,10 @@
// If the read index passed the write index then consider it an underrun.
if (mAudioEndpoint.getFullFramesAvailable() < 0) {
- ALOGV("AudioStreamInternal::processDataNow() - XRun! write = %d, read = %d",
- (int)mAudioEndpoint.getDataWriteCounter(),
- (int)mAudioEndpoint.getDataReadCounter());
mXRunCount++;
+ if (ATRACE_ENABLED()) {
+ ATRACE_INT("aaUnderRuns", mXRunCount);
+ }
}
// Write some data to the buffer.
@@ -119,6 +127,9 @@
int32_t framesWritten = writeNowWithConversion(buffer, numFrames);
//ALOGD("AudioStreamInternal::processDataNow() - tried to write %d frames, wrote %d",
// numFrames, framesWritten);
+ if (ATRACE_ENABLED()) {
+ ATRACE_INT("aaWrote", framesWritten);
+ }
// Calculate an ideal time to wake up.
if (wakeTimePtr != nullptr && framesWritten >= 0) {
@@ -135,14 +146,15 @@
wakeTime = currentNanoTime;
}
break;
- case AAUDIO_STREAM_STATE_STARTED: // When do we expect the next read burst to occur?
+ case AAUDIO_STREAM_STATE_STARTED:
{
- uint32_t burstSize = mFramesPerBurst;
- if (burstSize < 32) {
- burstSize = 32; // TODO review
- }
+ // When do we expect the next read burst to occur?
- uint64_t nextReadPosition = mAudioEndpoint.getDataReadCounter() + burstSize;
+ // Calculate frame position based off of the writeCounter because
+ // the readCounter might have just advanced in the background,
+ // causing us to sleep until a later burst.
+ int64_t nextReadPosition = mAudioEndpoint.getDataWriteCounter() + mFramesPerBurst
+ - mAudioEndpoint.getBufferSizeInFrames();
wakeTime = mClockModel.convertPositionToTime(nextReadPosition);
}
break;
@@ -152,10 +164,8 @@
*wakeTimePtr = wakeTime;
}
-// ALOGD("AudioStreamInternal::processDataNow finished: now = %llu, read# = %llu, wrote# = %llu",
-// (unsigned long long)currentNanoTime,
-// (unsigned long long)mAudioEndpoint.getDataReadCounter(),
-// (unsigned long long)mAudioEndpoint.getDownDataWriteCounter());
+
+ ATRACE_END();
return framesWritten;
}
@@ -170,7 +180,7 @@
mAudioEndpoint.getEmptyFramesAvailable(&wrappingBuffer);
- // Read data in one or two parts.
+ // Write data in one or two parts.
int partIndex = 0;
while (framesLeft > 0 && partIndex < WrappingBuffer::SIZE) {
int32_t framesToWrite = framesLeft;
@@ -291,6 +301,7 @@
aaudio_data_callback_result_t callbackResult = AAUDIO_CALLBACK_RESULT_CONTINUE;
AAudioStream_dataCallback appCallback = getDataCallbackProc();
if (appCallback == nullptr) return NULL;
+ int64_t timeoutNanos = calculateReasonableTimeout(mCallbackFrames);
// result might be a frame count
while (mCallbackEnabled.load() && isActive() && (result >= 0)) {
@@ -302,10 +313,7 @@
mCallbackFrames);
if (callbackResult == AAUDIO_CALLBACK_RESULT_CONTINUE) {
- // Write audio data to stream.
- int64_t timeoutNanos = calculateReasonableTimeout(mCallbackFrames);
-
- // This is a BLOCKING WRITE!
+ // Write audio data to stream. This is a BLOCKING WRITE!
result = write(mCallbackBuffer, mCallbackFrames, timeoutNanos);
if ((result != mCallbackFrames)) {
ALOGE("AudioStreamInternalPlay(): callbackLoop: write() returned %d", result);