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/*
* 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:
explicit 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