am 20398fac: Merge "audioflinger: reduce sleep time to avoid underrun" into ics-mr1
* commit '20398fac99ff78cb3ec3dd122930e45d409e0524':
audioflinger: reduce sleep time to avoid underrun
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 780c0d2..aea31a8 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -89,6 +89,12 @@
static const nsecs_t kSetParametersTimeout = seconds(2);
+// minimum sleep time for the mixer thread loop when tracks are active but in underrun
+static const uint32_t kMinThreadSleepTimeUs = 5000;
+// maximum divider applied to the active sleep time in the mixer thread loop
+static const uint32_t kMaxThreadSleepTimeShift = 2;
+
+
// ----------------------------------------------------------------------------
static bool recordingAllowed() {
@@ -1846,6 +1852,7 @@
uint32_t activeSleepTime = activeSleepTimeUs();
uint32_t idleSleepTime = idleSleepTimeUs();
uint32_t sleepTime = idleSleepTime;
+ uint32_t sleepTimeShift = 0;
Vector< sp<EffectChain> > effectChains;
#ifdef DEBUG_CPU_USAGE
ThreadCpuUsage cpu;
@@ -1937,6 +1944,7 @@
standbyTime = systemTime() + kStandbyTimeInNsecs;
sleepTime = idleSleepTime;
+ sleepTimeShift = 0;
continue;
}
}
@@ -1953,6 +1961,10 @@
// mix buffers...
mAudioMixer->process();
sleepTime = 0;
+ // increase sleep time progressively when application underrun condition clears
+ if (sleepTimeShift > 0) {
+ sleepTimeShift--;
+ }
standbyTime = systemTime() + kStandbyTimeInNsecs;
//TODO: delay standby when effects have a tail
} else {
@@ -1960,7 +1972,17 @@
// buffer size, then write 0s to the output
if (sleepTime == 0) {
if (mixerStatus == MIXER_TRACKS_ENABLED) {
- sleepTime = activeSleepTime;
+ sleepTime = activeSleepTime >> sleepTimeShift;
+ if (sleepTime < kMinThreadSleepTimeUs) {
+ sleepTime = kMinThreadSleepTimeUs;
+ }
+ // reduce sleep time in case of consecutive application underruns to avoid
+ // starving the audio HAL. As activeSleepTimeUs() is larger than a buffer
+ // duration we would end up writing less data than needed by the audio HAL if
+ // the condition persists.
+ if (sleepTimeShift < kMaxThreadSleepTimeShift) {
+ sleepTimeShift++;
+ }
} else {
sleepTime = idleSleepTime;
}