aaudio: control MMAP mode using system properties
To facilitate testing of MMAP mode.
Bug: 38268547
Test: set properties, see framesPerBurst in write_sine_callback.cpp
Change-Id: I6e15c563215017f6a5020d89ac312ff8331afc4f
Signed-off-by: Phil Burk <philburk@google.com>
diff --git a/services/oboeservice/AAudioServiceStreamMMAP.cpp b/services/oboeservice/AAudioServiceStreamMMAP.cpp
index cadc2a4..78a1583 100644
--- a/services/oboeservice/AAudioServiceStreamMMAP.cpp
+++ b/services/oboeservice/AAudioServiceStreamMMAP.cpp
@@ -178,6 +178,21 @@
mAudioFormat = AAudioConvert_androidToAAudioDataFormat(config.format);
mSampleRate = config.sample_rate;
+ // Scale up the burst size to meet the minimum equivalent in microseconds.
+ // This is to avoid waking the CPU too often when the HW burst is very small
+ // or at high sample rates.
+ int32_t burstMinMicros = AAudioProperty_getHardwareBurstMinMicros();
+ int32_t burstMicros = 0;
+ do {
+ if (burstMicros > 0) { // skip first loop
+ mFramesPerBurst *= 2;
+ }
+ burstMicros = mFramesPerBurst * static_cast<int64_t>(1000000) / mSampleRate;
+ } while (burstMicros < burstMinMicros);
+
+ ALOGD("AAudioServiceStreamMMAP::open() original burst = %d, minMicros = %d, final burst = %d\n",
+ mMmapBufferinfo.burst_size_frames, burstMinMicros, mFramesPerBurst);
+
ALOGD("AAudioServiceStreamMMAP::open() got devId = %d, sRate = %d",
deviceId, config.sample_rate);