Merge "Throttle MixerThread data pull to no more than twice expected rate" into mnc-dev
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 7809eff..dc6710f 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -2191,6 +2191,10 @@
ALOGI("HAL output buffer size %u frames, normal sink buffer size %u frames", mFrameCount,
mNormalFrameCount);
+ // Check if we want to throttle the processing to no more than 2x normal rate
+ mThreadThrottle = property_get_bool("af.thread.throttle", true /* default_value */);
+ mHalfBufferMs = mNormalFrameCount * 1000 / (2 * mSampleRate);
+
// mSinkBuffer is the sink buffer. Size is always multiple-of-16 frames.
// Originally this was int16_t[] array, need to remove legacy implications.
free(mSinkBuffer);
@@ -2908,8 +2912,9 @@
if (!waitingAsyncCallback()) {
// mSleepTimeUs == 0 means we must write to audio hardware
if (mSleepTimeUs == 0) {
+ ssize_t ret = 0;
if (mBytesRemaining) {
- ssize_t ret = threadLoop_write();
+ ret = threadLoop_write();
if (ret < 0) {
mBytesRemaining = 0;
} else {
@@ -2920,11 +2925,11 @@
(mMixerStatus == MIXER_DRAIN_ALL)) {
threadLoop_drain();
}
- if (mType == MIXER) {
+ if (mType == MIXER && !mStandby) {
// write blocked detection
nsecs_t now = systemTime();
nsecs_t delta = now - mLastWriteTime;
- if (!mStandby && delta > maxPeriod) {
+ if (delta > maxPeriod) {
mNumDelayedWrites++;
if ((now - lastWarning) > kWarningThrottleNs) {
ATRACE_NAME("underrun");
@@ -2933,6 +2938,31 @@
lastWarning = now;
}
}
+
+ if (mThreadThrottle
+ && mMixerStatus == MIXER_TRACKS_READY // we are mixing (active tracks)
+ && ret > 0) { // we wrote something
+ // Limit MixerThread data processing to no more than twice the
+ // expected processing rate.
+ //
+ // This helps prevent underruns with NuPlayer and other applications
+ // which may set up buffers that are close to the minimum size, or use
+ // deep buffers, and rely on a double-buffering sleep strategy to fill.
+ //
+ // The throttle smooths out sudden large data drains from the device,
+ // e.g. when it comes out of standby, which often causes problems with
+ // (1) mixer threads without a fast mixer (which has its own warm-up)
+ // (2) minimum buffer sized tracks (even if the track is full,
+ // the app won't fill fast enough to handle the sudden draw).
+
+ const int32_t deltaMs = delta / 1000000;
+ const int32_t throttleMs = mHalfBufferMs - deltaMs;
+ if ((signed)mHalfBufferMs >= throttleMs && throttleMs > 0) {
+ usleep(throttleMs * 1000);
+ ALOGD("mixer(%p) throttle: ret(%zd) deltaMs(%d) requires sleep %d ms",
+ this, ret, deltaMs, throttleMs);
+ }
+ }
}
} else {
@@ -4023,6 +4053,8 @@
}
} else {
if (framesReady < desiredFrames && !track->isStopped() && !track->isPaused()) {
+ ALOGV("track(%p) underrun, framesReady(%zu) < framesDesired(%zd)",
+ track, framesReady, desiredFrames);
track->mAudioTrackServerProxy->tallyUnderrunFrames(desiredFrames);
}
// clear effect chain input buffer if an active track underruns to avoid sending
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 07c226e..7b4fb14 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -613,6 +613,9 @@
// updated by readOutputParameters_l()
size_t mNormalFrameCount; // normal mixer and effects
+ bool mThreadThrottle; // throttle the thread processing
+ uint32_t mHalfBufferMs; // half the buffer size in milliseconds
+
void* mSinkBuffer; // frame size aligned sink buffer
// TODO: