Add audio watchdog thread
Change-Id: I4ed62087bd6554179abb8258d2da606050e762c0
diff --git a/services/audioflinger/AudioWatchdog.h b/services/audioflinger/AudioWatchdog.h
new file mode 100644
index 0000000..4657530
--- /dev/null
+++ b/services/audioflinger/AudioWatchdog.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// The watchdog thread runs periodically. It has two functions:
+// (a) verify that adequate CPU time is available, and log
+// as soon as possible when there appears to be a CPU shortage
+// (b) monitor the other threads [not yet implemented]
+
+#ifndef AUDIO_WATCHDOG_H
+#define AUDIO_WATCHDOG_H
+
+#include <time.h>
+#include <utils/Thread.h>
+
+namespace android {
+
+// Keeps a cache of AudioWatchdog statistics that can be logged by dumpsys.
+// The usual caveats about atomicity of information apply.
+struct AudioWatchdogDump {
+ AudioWatchdogDump() : mUnderruns(0), mLogs(0), mMostRecent(0) { }
+ /*virtual*/ ~AudioWatchdogDump() { }
+ uint32_t mUnderruns; // total number of underruns
+ uint32_t mLogs; // total number of log messages
+ time_t mMostRecent; // time of most recent log
+ void dump(int fd); // should only be called on a stable copy, not the original
+};
+
+class AudioWatchdog : public Thread {
+
+public:
+ AudioWatchdog(unsigned periodMs = 50) : Thread(false /*canCallJava*/), mPaused(false),
+ mPeriodNs(periodMs * 1000000), mMaxCycleNs(mPeriodNs * 2),
+ // mOldTs
+ // mLogTs initialized below
+ mOldTsValid(false), mUnderruns(0), mLogs(0), mDump(&mDummyDump)
+ {
+#define MIN_TIME_BETWEEN_LOGS_SEC 60
+ // force an immediate log on first underrun
+ mLogTs.tv_sec = MIN_TIME_BETWEEN_LOGS_SEC;
+ mLogTs.tv_nsec = 0;
+ }
+ virtual ~AudioWatchdog() { }
+
+ // Do not call Thread::requestExitAndWait() without first calling requestExit().
+ // Thread::requestExitAndWait() is not virtual, and the implementation doesn't do enough.
+ virtual void requestExit();
+
+ // FIXME merge API and implementation with AudioTrackThread
+ void pause(); // suspend thread from execution at next loop boundary
+ void resume(); // allow thread to execute, if not requested to exit
+
+ // Where to store the dump, or NULL to not update
+ void setDump(AudioWatchdogDump* dump);
+
+private:
+ virtual bool threadLoop();
+
+ Mutex mMyLock; // Thread::mLock is private
+ Condition mMyCond; // Thread::mThreadExitedCondition is private
+ bool mPaused; // whether thread is currently paused
+
+ uint32_t mPeriodNs; // nominal period
+ uint32_t mMaxCycleNs; // maximum allowed time of one cycle before declaring underrun
+ struct timespec mOldTs; // monotonic time when threadLoop last ran
+ struct timespec mLogTs; // time since last log
+ bool mOldTsValid; // whether mOldTs is valid
+ uint32_t mUnderruns; // total number of underruns
+ uint32_t mLogs; // total number of logs
+ AudioWatchdogDump* mDump; // where to store the dump, always non-NULL
+ AudioWatchdogDump mDummyDump; // default area for dump in case setDump() is not called
+};
+
+} // namespace android
+
+#endif // AUDIO_WATCHDOG_H