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/utility/AAudioUtilities.h b/media/libaaudio/src/utility/AAudioUtilities.h
index efd663d..acd319b 100644
--- a/media/libaaudio/src/utility/AAudioUtilities.h
+++ b/media/libaaudio/src/utility/AAudioUtilities.h
@@ -195,13 +195,35 @@
/**
* Read system property.
- * @return number of bursts per mixer cycle
+ * @return number of bursts per AAudio service mixer cycle
*/
int32_t AAudioProperty_getMixerBursts();
#define AAUDIO_PROP_HW_BURST_MIN_USEC "aaudio.hw_burst_min_usec"
/**
+ * Read a system property that specifies the number of extra microseconds that a thread
+ * should sleep when waiting for another thread to service a FIFO. This is used
+ * to avoid the waking thread from being overly optimistic about the other threads
+ * wakeup timing. This value should be set high enough to cover typical scheduling jitter
+ * for a real-time thread.
+ *
+ * @return number of microseconds to delay the wakeup.
+ */
+int32_t AAudioProperty_getWakeupDelayMicros();
+
+#define AAUDIO_PROP_WAKEUP_DELAY_USEC "aaudio.wakeup_delay_usec"
+
+/**
+ * Read a system property that specifies the minimum sleep time when polling the FIFO.
+ *
+ * @return minimum number of microseconds to sleep.
+ */
+int32_t AAudioProperty_getMinimumSleepMicros();
+
+#define AAUDIO_PROP_MINIMUM_SLEEP_USEC "aaudio.minimum_sleep_usec"
+
+/**
* Read system property.
* This is handy in case the DMA is bursting too quickly for the CPU to keep up.
* For example, there may be a DMA burst every 100 usec but you only