From 97b5d0d5b5ef766eb5dd680d05a5d199662d4ae0 Mon Sep 17 00:00:00 2001 From: Glenn Kasten Date: Fri, 23 Mar 2012 18:54:19 -0700 Subject: Fast mixer Change-Id: I61552f83507e08e4c706076b9fb15362869e6265 --- services/audioflinger/FastMixer.cpp | 454 ++++++++++++++++++++++++++++++++++++ 1 file changed, 454 insertions(+) create mode 100644 services/audioflinger/FastMixer.cpp (limited to 'services/audioflinger/FastMixer.cpp') diff --git a/services/audioflinger/FastMixer.cpp b/services/audioflinger/FastMixer.cpp new file mode 100644 index 0000000..1543152 --- /dev/null +++ b/services/audioflinger/FastMixer.cpp @@ -0,0 +1,454 @@ +/* + * 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. + */ + +#define LOG_TAG "FastMixer" +//#define LOG_NDEBUG 0 + +#include +#include +#include +#include +#ifdef FAST_MIXER_STATISTICS +#include +#endif +#include "AudioMixer.h" +#include "FastMixer.h" + +#define FAST_HOT_IDLE_NS 1000000L // 1 ms: time to sleep while hot idling +#define FAST_DEFAULT_NS 999999999L // ~1 sec: default time to sleep + +namespace android { + +// Fast mixer thread +bool FastMixer::threadLoop() +{ + static const FastMixerState initial; + const FastMixerState *previous = &initial, *current = &initial; + FastMixerState preIdle; // copy of state before we went into idle + struct timespec oldTs = {0, 0}; + bool oldTsValid = false; + long slopNs = 0; // accumulated time we've woken up too early (> 0) or too late (< 0) + long sleepNs = -1; // -1: busy wait, 0: sched_yield, > 0: nanosleep + int fastTrackNames[FastMixerState::kMaxFastTracks]; // handles used by mixer to identify tracks + int generations[FastMixerState::kMaxFastTracks]; // last observed mFastTracks[i].mGeneration + unsigned i; + for (i = 0; i < FastMixerState::kMaxFastTracks; ++i) { + fastTrackNames[i] = -1; + generations[i] = 0; + } + NBAIO_Sink *outputSink = NULL; + int outputSinkGen = 0; + AudioMixer* mixer = NULL; + short *mixBuffer = NULL; + enum {UNDEFINED, MIXED, ZEROED} mixBufferState = UNDEFINED; + NBAIO_Format format = Format_Invalid; + unsigned sampleRate = 0; + int fastTracksGen = 0; + long periodNs = 0; // expected period; the time required to render one mix buffer + long underrunNs = 0; // an underrun is likely if an actual cycle is greater than this value + long overrunNs = 0; // an overrun is likely if an actual cycle if less than this value + FastMixerDumpState dummyDumpState, *dumpState = &dummyDumpState; + bool ignoreNextOverrun = true; // used to ignore initial overrun and first after an underrun +#ifdef FAST_MIXER_STATISTICS + CentralTendencyStatistics cts; // cycle times in seconds + static const unsigned kMaxSamples = 1000; +#endif + unsigned coldGen = 0; // last observed mColdGen + + for (;;) { + + // either nanosleep, sched_yield, or busy wait + if (sleepNs >= 0) { + if (sleepNs > 0) { + ALOG_ASSERT(sleepNs < 1000000000); + const struct timespec req = {0, sleepNs}; + nanosleep(&req, NULL); + } else { + sched_yield(); + } + } + // default to long sleep for next cycle + sleepNs = FAST_DEFAULT_NS; + + // poll for state change + const FastMixerState *next = mSQ.poll(); + if (next == NULL) { + // continue to use the default initial state until a real state is available + ALOG_ASSERT(current == &initial && previous == &initial); + next = current; + } + + FastMixerState::Command command = next->mCommand; + if (next != current) { + + // As soon as possible of learning of a new dump area, start using it + dumpState = next->mDumpState != NULL ? next->mDumpState : &dummyDumpState; + + // We want to always have a valid reference to the previous (non-idle) state. + // However, the state queue only guarantees access to current and previous states. + // So when there is a transition from a non-idle state into an idle state, we make a + // copy of the last known non-idle state so it is still available on return from idle. + // The possible transitions are: + // non-idle -> non-idle update previous from current in-place + // non-idle -> idle update previous from copy of current + // idle -> idle don't update previous + // idle -> non-idle don't update previous + if (!(current->mCommand & FastMixerState::IDLE)) { + if (command & FastMixerState::IDLE) { + preIdle = *current; + current = &preIdle; + oldTsValid = false; + ignoreNextOverrun = true; + } + previous = current; + } + current = next; + } +#if !LOG_NDEBUG + next = NULL; // not referenced again +#endif + + dumpState->mCommand = command; + + switch (command) { + case FastMixerState::INITIAL: + case FastMixerState::HOT_IDLE: + sleepNs = FAST_HOT_IDLE_NS; + continue; + case FastMixerState::COLD_IDLE: + // only perform a cold idle command once + if (current->mColdGen != coldGen) { + int32_t *coldFutexAddr = current->mColdFutexAddr; + ALOG_ASSERT(coldFutexAddr != NULL); + int32_t old = android_atomic_dec(coldFutexAddr); + if (old <= 0) { + __futex_syscall4(coldFutexAddr, FUTEX_WAIT_PRIVATE, old - 1, NULL); + } + sleepNs = -1; + coldGen = current->mColdGen; + } else { + sleepNs = FAST_HOT_IDLE_NS; + } + continue; + case FastMixerState::EXIT: + delete mixer; + delete[] mixBuffer; + return false; + case FastMixerState::MIX: + case FastMixerState::WRITE: + case FastMixerState::MIX_WRITE: + break; + default: + LOG_FATAL("bad command %d", command); + } + + // there is a non-idle state available to us; did the state change? + size_t frameCount = current->mFrameCount; + if (current != previous) { + + // handle state change here, but since we want to diff the state, + // we're prepared for previous == &initial the first time through + unsigned previousTrackMask; + + // check for change in output HAL configuration + NBAIO_Format previousFormat = format; + if (current->mOutputSinkGen != outputSinkGen) { + outputSink = current->mOutputSink; + outputSinkGen = current->mOutputSinkGen; + if (outputSink == NULL) { + format = Format_Invalid; + sampleRate = 0; + } else { + format = outputSink->format(); + sampleRate = Format_sampleRate(format); + ALOG_ASSERT(Format_channelCount(format) == 2); + } + } + + if ((format != previousFormat) || (frameCount != previous->mFrameCount)) { + // FIXME to avoid priority inversion, don't delete here + delete mixer; + mixer = NULL; + delete[] mixBuffer; + mixBuffer = NULL; + if (frameCount > 0 && sampleRate > 0) { + // FIXME new may block for unbounded time at internal mutex of the heap + // implementation; it would be better to have normal mixer allocate for us + // to avoid blocking here and to prevent possible priority inversion + mixer = new AudioMixer(frameCount, sampleRate, FastMixerState::kMaxFastTracks); + mixBuffer = new short[frameCount * 2]; + periodNs = (frameCount * 1000000000LL) / sampleRate; // 1.00 + underrunNs = (frameCount * 1750000000LL) / sampleRate; // 1.75 + overrunNs = (frameCount * 250000000LL) / sampleRate; // 0.25 + } else { + periodNs = 0; + underrunNs = 0; + overrunNs = 0; + } + mixBufferState = UNDEFINED; +#if !LOG_NDEBUG + for (i = 0; i < FastMixerState::kMaxFastTracks; ++i) { + fastTrackNames[i] = -1; + } +#endif + // we need to reconfigure all active tracks + previousTrackMask = 0; + fastTracksGen = current->mFastTracksGen - 1; + } else { + previousTrackMask = previous->mTrackMask; + } + + // check for change in active track set + unsigned currentTrackMask = current->mTrackMask; + if (current->mFastTracksGen != fastTracksGen) { + ALOG_ASSERT(mixBuffer != NULL); + int name; + + // process removed tracks first to avoid running out of track names + unsigned removedTracks = previousTrackMask & ~currentTrackMask; + while (removedTracks != 0) { + i = __builtin_ctz(removedTracks); + removedTracks &= ~(1 << i); + const FastTrack* fastTrack = ¤t->mFastTracks[i]; + if (mixer != NULL) { + name = fastTrackNames[i]; + ALOG_ASSERT(name >= 0); + mixer->deleteTrackName(name); + } +#if !LOG_NDEBUG + fastTrackNames[i] = -1; +#endif + generations[i] = fastTrack->mGeneration; + } + + // now process added tracks + unsigned addedTracks = currentTrackMask & ~previousTrackMask; + while (addedTracks != 0) { + i = __builtin_ctz(addedTracks); + addedTracks &= ~(1 << i); + const FastTrack* fastTrack = ¤t->mFastTracks[i]; + AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider; + ALOG_ASSERT(bufferProvider != NULL && fastTrackNames[i] == -1); + if (mixer != NULL) { + name = mixer->getTrackName(); + ALOG_ASSERT(name >= 0); + fastTrackNames[i] = name; + mixer->setBufferProvider(name, bufferProvider); + mixer->setParameter(name, AudioMixer::TRACK, AudioMixer::MAIN_BUFFER, + (void *) mixBuffer); + // newly allocated track names default to full scale volume + mixer->enable(name); + } + generations[i] = fastTrack->mGeneration; + } + + // finally process modified tracks; these use the same slot + // but may have a different buffer provider or volume provider + unsigned modifiedTracks = currentTrackMask & previousTrackMask; + while (modifiedTracks != 0) { + i = __builtin_ctz(modifiedTracks); + modifiedTracks &= ~(1 << i); + const FastTrack* fastTrack = ¤t->mFastTracks[i]; + if (fastTrack->mGeneration != generations[i]) { + AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider; + ALOG_ASSERT(bufferProvider != NULL); + if (mixer != NULL) { + name = fastTrackNames[i]; + ALOG_ASSERT(name >= 0); + mixer->setBufferProvider(name, bufferProvider); + if (fastTrack->mVolumeProvider == NULL) { + mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME0, + (void *)0x1000); + mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME1, + (void *)0x1000); + } + // already enabled + } + generations[i] = fastTrack->mGeneration; + } + } + + fastTracksGen = current->mFastTracksGen; + + dumpState->mNumTracks = popcount(currentTrackMask); + } + +#if 1 // FIXME shouldn't need this + // only process state change once + previous = current; +#endif + } + + // do work using current state here + if ((command & FastMixerState::MIX) && (mixer != NULL)) { + ALOG_ASSERT(mixBuffer != NULL); + // update volumes + unsigned volumeTracks = current->mTrackMask; + while (volumeTracks != 0) { + i = __builtin_ctz(volumeTracks); + volumeTracks &= ~(1 << i); + const FastTrack* fastTrack = ¤t->mFastTracks[i]; + int name = fastTrackNames[i]; + ALOG_ASSERT(name >= 0); + if (fastTrack->mVolumeProvider != NULL) { + uint32_t vlr = fastTrack->mVolumeProvider->getVolumeLR(); + mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME0, + (void *)(vlr & 0xFFFF)); + mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME1, + (void *)(vlr >> 16)); + } + } + // process() is CPU-bound + mixer->process(AudioBufferProvider::kInvalidPTS); + mixBufferState = MIXED; + } else if (mixBufferState == MIXED) { + mixBufferState = UNDEFINED; + } + if ((command & FastMixerState::WRITE) && (outputSink != NULL) && (mixBuffer != NULL)) { + if (mixBufferState == UNDEFINED) { + memset(mixBuffer, 0, frameCount * 2 * sizeof(short)); + mixBufferState = ZEROED; + } + // FIXME write() is non-blocking and lock-free for a properly implemented NBAIO sink, + // but this code should be modified to handle both non-blocking and blocking sinks + dumpState->mWriteSequence++; + ssize_t framesWritten = outputSink->write(mixBuffer, frameCount); + dumpState->mWriteSequence++; + if (framesWritten >= 0) { + dumpState->mFramesWritten += framesWritten; + } else { + dumpState->mWriteErrors++; + } + // FIXME count # of writes blocked excessively, CPU usage, etc. for dump + } + + // To be exactly periodic, compute the next sleep time based on current time. + // This code doesn't have long-term stability when the sink is non-blocking. + // FIXME To avoid drift, use the local audio clock or watch the sink's fill status. + struct timespec newTs; + int rc = clock_gettime(CLOCK_MONOTONIC, &newTs); + if (rc == 0) { + if (oldTsValid) { + time_t sec = newTs.tv_sec - oldTs.tv_sec; + long nsec = newTs.tv_nsec - oldTs.tv_nsec; + if (nsec < 0) { + --sec; + nsec += 1000000000; + } + if (sec > 0 || nsec > underrunNs) { + // FIXME only log occasionally + ALOGV("underrun: time since last cycle %d.%03ld sec", + (int) sec, nsec / 1000000L); + dumpState->mUnderruns++; + sleepNs = -1; + ignoreNextOverrun = true; + } else if (nsec < overrunNs) { + if (ignoreNextOverrun) { + ignoreNextOverrun = false; + } else { + // FIXME only log occasionally + ALOGV("overrun: time since last cycle %d.%03ld sec", + (int) sec, nsec / 1000000L); + dumpState->mOverruns++; + } + sleepNs = periodNs - overrunNs; + } else { + sleepNs = -1; + ignoreNextOverrun = false; + } +#ifdef FAST_MIXER_STATISTICS + // long-term statistics + cts.sample(sec + nsec * 1e-9); + if (cts.n() >= kMaxSamples) { + dumpState->mMean = cts.mean(); + dumpState->mMinimum = cts.minimum(); + dumpState->mMaximum = cts.maximum(); + dumpState->mStddev = cts.stddev(); + cts.reset(); + } +#endif + } else { + // first time through the loop + oldTsValid = true; + sleepNs = periodNs; + ignoreNextOverrun = true; + } + oldTs = newTs; + } else { + // monotonic clock is broken + oldTsValid = false; + sleepNs = periodNs; + } + + } // for (;;) + + // never return 'true'; Thread::_threadLoop() locks mutex which can result in priority inversion +} + +FastMixerDumpState::FastMixerDumpState() : + mCommand(FastMixerState::INITIAL), mWriteSequence(0), mFramesWritten(0), + mNumTracks(0), mWriteErrors(0), mUnderruns(0), mOverruns(0) +#ifdef FAST_MIXER_STATISTICS + , mMean(0.0), mMinimum(0.0), mMaximum(0.0), mStddev(0.0) +#endif +{ +} + +FastMixerDumpState::~FastMixerDumpState() +{ +} + +void FastMixerDumpState::dump(int fd) +{ +#define COMMAND_MAX 32 + char string[COMMAND_MAX]; + switch (mCommand) { + case FastMixerState::INITIAL: + strcpy(string, "INITIAL"); + break; + case FastMixerState::HOT_IDLE: + strcpy(string, "HOT_IDLE"); + break; + case FastMixerState::COLD_IDLE: + strcpy(string, "COLD_IDLE"); + break; + case FastMixerState::EXIT: + strcpy(string, "EXIT"); + break; + case FastMixerState::MIX: + strcpy(string, "MIX"); + break; + case FastMixerState::WRITE: + strcpy(string, "WRITE"); + break; + case FastMixerState::MIX_WRITE: + strcpy(string, "MIX_WRITE"); + break; + default: + snprintf(string, COMMAND_MAX, "%d", mCommand); + break; + } + fdprintf(fd, "FastMixer command=%s writeSequence=%u framesWritten=%u\n" + " numTracks=%u writeErrors=%u underruns=%u overruns=%u\n", + string, mWriteSequence, mFramesWritten, + mNumTracks, mWriteErrors, mUnderruns, mOverruns); +#ifdef FAST_MIXER_STATISTICS + fdprintf(fd, " cycle time in ms: mean=%.1f min=%.1f max=%.1f stddev=%.1f\n", + mMean*1e3, mMinimum*1e3, mMaximum*1e3, mStddev*1e3); +#endif +} + +} // namespace android -- cgit v1.1