FastMixer.cpp revision 1295bb4dcff7b29c75cd23746816df12a871d72c
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#define LOG_TAG "FastMixer"
18//#define LOG_NDEBUG 0
19
20#include <sys/atomics.h>
21#include <time.h>
22#include <utils/Log.h>
23#include <utils/Trace.h>
24#include <system/audio.h>
25#ifdef FAST_MIXER_STATISTICS
26#include <cpustats/CentralTendencyStatistics.h>
27#include <cpustats/ThreadCpuUsage.h>
28#endif
29#include "AudioMixer.h"
30#include "FastMixer.h"
31
32#define FAST_HOT_IDLE_NS     1000000L   // 1 ms: time to sleep while hot idling
33#define FAST_DEFAULT_NS    999999999L   // ~1 sec: default time to sleep
34#define MAX_WARMUP_CYCLES         10    // maximum number of loop cycles to wait for warmup
35
36namespace android {
37
38// Fast mixer thread
39bool FastMixer::threadLoop()
40{
41    static const FastMixerState initial;
42    const FastMixerState *previous = &initial, *current = &initial;
43    FastMixerState preIdle; // copy of state before we went into idle
44    struct timespec oldTs = {0, 0};
45    bool oldTsValid = false;
46    long slopNs = 0;    // accumulated time we've woken up too early (> 0) or too late (< 0)
47    long sleepNs = -1;  // -1: busy wait, 0: sched_yield, > 0: nanosleep
48    int fastTrackNames[FastMixerState::kMaxFastTracks]; // handles used by mixer to identify tracks
49    int generations[FastMixerState::kMaxFastTracks];    // last observed mFastTracks[i].mGeneration
50    unsigned i;
51    for (i = 0; i < FastMixerState::kMaxFastTracks; ++i) {
52        fastTrackNames[i] = -1;
53        generations[i] = 0;
54    }
55    NBAIO_Sink *outputSink = NULL;
56    int outputSinkGen = 0;
57    AudioMixer* mixer = NULL;
58    short *mixBuffer = NULL;
59    enum {UNDEFINED, MIXED, ZEROED} mixBufferState = UNDEFINED;
60    NBAIO_Format format = Format_Invalid;
61    unsigned sampleRate = 0;
62    int fastTracksGen = 0;
63    long periodNs = 0;      // expected period; the time required to render one mix buffer
64    long underrunNs = 0;    // underrun likely when write cycle is greater than this value
65    long overrunNs = 0;     // overrun likely when write cycle is less than this value
66    long warmupNs = 0;      // warmup complete when write cycle is greater than to this value
67    FastMixerDumpState dummyDumpState, *dumpState = &dummyDumpState;
68    bool ignoreNextOverrun = true;  // used to ignore initial overrun and first after an underrun
69#ifdef FAST_MIXER_STATISTICS
70    struct timespec oldLoad = {0, 0};    // previous value of clock_gettime(CLOCK_THREAD_CPUTIME_ID)
71    bool oldLoadValid = false;  // whether oldLoad is valid
72    uint32_t bounds = 0;
73    bool full = false;      // whether we have collected at least kSamplingN samples
74    ThreadCpuUsage tcu;     // for reading the current CPU clock frequency in kHz
75#endif
76    unsigned coldGen = 0;   // last observed mColdGen
77    bool isWarm = false;    // true means ready to mix, false means wait for warmup before mixing
78    struct timespec measuredWarmupTs = {0, 0};  // how long did it take for warmup to complete
79    uint32_t warmupCycles = 0;  // counter of number of loop cycles required to warmup
80    NBAIO_Sink* teeSink = NULL; // if non-NULL, then duplicate write() to this non-blocking sink
81
82    for (;;) {
83
84        // either nanosleep, sched_yield, or busy wait
85        if (sleepNs >= 0) {
86            if (sleepNs > 0) {
87                ALOG_ASSERT(sleepNs < 1000000000);
88                const struct timespec req = {0, sleepNs};
89                nanosleep(&req, NULL);
90            } else {
91                sched_yield();
92            }
93        }
94        // default to long sleep for next cycle
95        sleepNs = FAST_DEFAULT_NS;
96
97        // poll for state change
98        const FastMixerState *next = mSQ.poll();
99        if (next == NULL) {
100            // continue to use the default initial state until a real state is available
101            ALOG_ASSERT(current == &initial && previous == &initial);
102            next = current;
103        }
104
105        FastMixerState::Command command = next->mCommand;
106        if (next != current) {
107
108            // As soon as possible of learning of a new dump area, start using it
109            dumpState = next->mDumpState != NULL ? next->mDumpState : &dummyDumpState;
110            teeSink = next->mTeeSink;
111
112            // We want to always have a valid reference to the previous (non-idle) state.
113            // However, the state queue only guarantees access to current and previous states.
114            // So when there is a transition from a non-idle state into an idle state, we make a
115            // copy of the last known non-idle state so it is still available on return from idle.
116            // The possible transitions are:
117            //  non-idle -> non-idle    update previous from current in-place
118            //  non-idle -> idle        update previous from copy of current
119            //  idle     -> idle        don't update previous
120            //  idle     -> non-idle    don't update previous
121            if (!(current->mCommand & FastMixerState::IDLE)) {
122                if (command & FastMixerState::IDLE) {
123                    preIdle = *current;
124                    current = &preIdle;
125                    oldTsValid = false;
126                    oldLoadValid = false;
127                    ignoreNextOverrun = true;
128                }
129                previous = current;
130            }
131            current = next;
132        }
133#if !LOG_NDEBUG
134        next = NULL;    // not referenced again
135#endif
136
137        dumpState->mCommand = command;
138
139        switch (command) {
140        case FastMixerState::INITIAL:
141        case FastMixerState::HOT_IDLE:
142            sleepNs = FAST_HOT_IDLE_NS;
143            continue;
144        case FastMixerState::COLD_IDLE:
145            // only perform a cold idle command once
146            // FIXME consider checking previous state and only perform if previous != COLD_IDLE
147            if (current->mColdGen != coldGen) {
148                int32_t *coldFutexAddr = current->mColdFutexAddr;
149                ALOG_ASSERT(coldFutexAddr != NULL);
150                int32_t old = android_atomic_dec(coldFutexAddr);
151                if (old <= 0) {
152                    __futex_syscall4(coldFutexAddr, FUTEX_WAIT_PRIVATE, old - 1, NULL);
153                }
154                // This may be overly conservative; there could be times that the normal mixer
155                // requests such a brief cold idle that it doesn't require resetting this flag.
156                isWarm = false;
157                measuredWarmupTs.tv_sec = 0;
158                measuredWarmupTs.tv_nsec = 0;
159                warmupCycles = 0;
160                sleepNs = -1;
161                coldGen = current->mColdGen;
162                bounds = 0;
163                full = false;
164                oldTsValid = !clock_gettime(CLOCK_MONOTONIC, &oldTs);
165            } else {
166                sleepNs = FAST_HOT_IDLE_NS;
167            }
168            continue;
169        case FastMixerState::EXIT:
170            delete mixer;
171            delete[] mixBuffer;
172            return false;
173        case FastMixerState::MIX:
174        case FastMixerState::WRITE:
175        case FastMixerState::MIX_WRITE:
176            break;
177        default:
178            LOG_FATAL("bad command %d", command);
179        }
180
181        // there is a non-idle state available to us; did the state change?
182        size_t frameCount = current->mFrameCount;
183        if (current != previous) {
184
185            // handle state change here, but since we want to diff the state,
186            // we're prepared for previous == &initial the first time through
187            unsigned previousTrackMask;
188
189            // check for change in output HAL configuration
190            NBAIO_Format previousFormat = format;
191            if (current->mOutputSinkGen != outputSinkGen) {
192                outputSink = current->mOutputSink;
193                outputSinkGen = current->mOutputSinkGen;
194                if (outputSink == NULL) {
195                    format = Format_Invalid;
196                    sampleRate = 0;
197                } else {
198                    format = outputSink->format();
199                    sampleRate = Format_sampleRate(format);
200                    ALOG_ASSERT(Format_channelCount(format) == 2);
201                }
202                dumpState->mSampleRate = sampleRate;
203            }
204
205            if ((format != previousFormat) || (frameCount != previous->mFrameCount)) {
206                // FIXME to avoid priority inversion, don't delete here
207                delete mixer;
208                mixer = NULL;
209                delete[] mixBuffer;
210                mixBuffer = NULL;
211                if (frameCount > 0 && sampleRate > 0) {
212                    // FIXME new may block for unbounded time at internal mutex of the heap
213                    //       implementation; it would be better to have normal mixer allocate for us
214                    //       to avoid blocking here and to prevent possible priority inversion
215                    mixer = new AudioMixer(frameCount, sampleRate, FastMixerState::kMaxFastTracks);
216                    mixBuffer = new short[frameCount * 2];
217                    periodNs = (frameCount * 1000000000LL) / sampleRate;    // 1.00
218                    underrunNs = (frameCount * 1750000000LL) / sampleRate;  // 1.75
219                    overrunNs = (frameCount * 250000000LL) / sampleRate;    // 0.25
220                    warmupNs = (frameCount * 500000000LL) / sampleRate;     // 0.50
221                } else {
222                    periodNs = 0;
223                    underrunNs = 0;
224                    overrunNs = 0;
225                }
226                mixBufferState = UNDEFINED;
227#if !LOG_NDEBUG
228                for (i = 0; i < FastMixerState::kMaxFastTracks; ++i) {
229                    fastTrackNames[i] = -1;
230                }
231#endif
232                // we need to reconfigure all active tracks
233                previousTrackMask = 0;
234                fastTracksGen = current->mFastTracksGen - 1;
235                dumpState->mFrameCount = frameCount;
236            } else {
237                previousTrackMask = previous->mTrackMask;
238            }
239
240            // check for change in active track set
241            unsigned currentTrackMask = current->mTrackMask;
242            dumpState->mTrackMask = currentTrackMask;
243            if (current->mFastTracksGen != fastTracksGen) {
244                ALOG_ASSERT(mixBuffer != NULL);
245                int name;
246
247                // process removed tracks first to avoid running out of track names
248                unsigned removedTracks = previousTrackMask & ~currentTrackMask;
249                while (removedTracks != 0) {
250                    i = __builtin_ctz(removedTracks);
251                    removedTracks &= ~(1 << i);
252                    const FastTrack* fastTrack = &current->mFastTracks[i];
253                    ALOG_ASSERT(fastTrack->mBufferProvider == NULL);
254                    if (mixer != NULL) {
255                        name = fastTrackNames[i];
256                        ALOG_ASSERT(name >= 0);
257                        mixer->deleteTrackName(name);
258                    }
259#if !LOG_NDEBUG
260                    fastTrackNames[i] = -1;
261#endif
262                    // don't reset track dump state, since other side is ignoring it
263                    generations[i] = fastTrack->mGeneration;
264                }
265
266                // now process added tracks
267                unsigned addedTracks = currentTrackMask & ~previousTrackMask;
268                while (addedTracks != 0) {
269                    i = __builtin_ctz(addedTracks);
270                    addedTracks &= ~(1 << i);
271                    const FastTrack* fastTrack = &current->mFastTracks[i];
272                    AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider;
273                    ALOG_ASSERT(bufferProvider != NULL && fastTrackNames[i] == -1);
274                    if (mixer != NULL) {
275                        // calling getTrackName with default channel mask
276                        name = mixer->getTrackName(AUDIO_CHANNEL_OUT_STEREO);
277                        ALOG_ASSERT(name >= 0);
278                        fastTrackNames[i] = name;
279                        mixer->setBufferProvider(name, bufferProvider);
280                        mixer->setParameter(name, AudioMixer::TRACK, AudioMixer::MAIN_BUFFER,
281                                (void *) mixBuffer);
282                        // newly allocated track names default to full scale volume
283                        if (fastTrack->mSampleRate != 0 && fastTrack->mSampleRate != sampleRate) {
284                            mixer->setParameter(name, AudioMixer::RESAMPLE,
285                                    AudioMixer::SAMPLE_RATE, (void*) fastTrack->mSampleRate);
286                        }
287                        mixer->setParameter(name, AudioMixer::TRACK, AudioMixer::CHANNEL_MASK,
288                                (void *) fastTrack->mChannelMask);
289                        mixer->enable(name);
290                    }
291                    generations[i] = fastTrack->mGeneration;
292                }
293
294                // finally process modified tracks; these use the same slot
295                // but may have a different buffer provider or volume provider
296                unsigned modifiedTracks = currentTrackMask & previousTrackMask;
297                while (modifiedTracks != 0) {
298                    i = __builtin_ctz(modifiedTracks);
299                    modifiedTracks &= ~(1 << i);
300                    const FastTrack* fastTrack = &current->mFastTracks[i];
301                    if (fastTrack->mGeneration != generations[i]) {
302                        AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider;
303                        ALOG_ASSERT(bufferProvider != NULL);
304                        if (mixer != NULL) {
305                            name = fastTrackNames[i];
306                            ALOG_ASSERT(name >= 0);
307                            mixer->setBufferProvider(name, bufferProvider);
308                            if (fastTrack->mVolumeProvider == NULL) {
309                                mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME0,
310                                        (void *)0x1000);
311                                mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME1,
312                                        (void *)0x1000);
313                            }
314                            if (fastTrack->mSampleRate != 0 &&
315                                    fastTrack->mSampleRate != sampleRate) {
316                                mixer->setParameter(name, AudioMixer::RESAMPLE,
317                                        AudioMixer::SAMPLE_RATE, (void*) fastTrack->mSampleRate);
318                            } else {
319                                mixer->setParameter(name, AudioMixer::RESAMPLE,
320                                        AudioMixer::REMOVE, NULL);
321                            }
322                            mixer->setParameter(name, AudioMixer::TRACK, AudioMixer::CHANNEL_MASK,
323                                    (void *) fastTrack->mChannelMask);
324                            // already enabled
325                        }
326                        generations[i] = fastTrack->mGeneration;
327                    }
328                }
329
330                fastTracksGen = current->mFastTracksGen;
331
332                dumpState->mNumTracks = popcount(currentTrackMask);
333            }
334
335#if 1   // FIXME shouldn't need this
336            // only process state change once
337            previous = current;
338#endif
339        }
340
341        // do work using current state here
342        if ((command & FastMixerState::MIX) && (mixer != NULL) && isWarm) {
343            ALOG_ASSERT(mixBuffer != NULL);
344            // for each track, update volume and check for underrun
345            unsigned currentTrackMask = current->mTrackMask;
346            while (currentTrackMask != 0) {
347                i = __builtin_ctz(currentTrackMask);
348                currentTrackMask &= ~(1 << i);
349                const FastTrack* fastTrack = &current->mFastTracks[i];
350                int name = fastTrackNames[i];
351                ALOG_ASSERT(name >= 0);
352                if (fastTrack->mVolumeProvider != NULL) {
353                    uint32_t vlr = fastTrack->mVolumeProvider->getVolumeLR();
354                    mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME0,
355                            (void *)(vlr & 0xFFFF));
356                    mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME1,
357                            (void *)(vlr >> 16));
358                }
359                // FIXME The current implementation of framesReady() for fast tracks
360                // takes a tryLock, which can block
361                // up to 1 ms.  If enough active tracks all blocked in sequence, this would result
362                // in the overall fast mix cycle being delayed.  Should use a non-blocking FIFO.
363                size_t framesReady = fastTrack->mBufferProvider->framesReady();
364#if defined(ATRACE_TAG) && (ATRACE_TAG != ATRACE_TAG_NEVER)
365                // I wish we had formatted trace names
366                char traceName[16];
367                strcpy(traceName, "framesReady");
368                traceName[11] = i + (i < 10 ? '0' : 'A' - 10);
369                traceName[12] = '\0';
370                ATRACE_INT(traceName, framesReady);
371#endif
372                FastTrackDump *ftDump = &dumpState->mTracks[i];
373                FastTrackUnderruns underruns = ftDump->mUnderruns;
374                if (framesReady < frameCount) {
375                    if (framesReady == 0) {
376                        underruns.mBitFields.mEmpty++;
377                        underruns.mBitFields.mMostRecent = UNDERRUN_EMPTY;
378                        mixer->disable(name);
379                    } else {
380                        // allow mixing partial buffer
381                        underruns.mBitFields.mPartial++;
382                        underruns.mBitFields.mMostRecent = UNDERRUN_PARTIAL;
383                        mixer->enable(name);
384                    }
385                } else {
386                    underruns.mBitFields.mFull++;
387                    underruns.mBitFields.mMostRecent = UNDERRUN_FULL;
388                    mixer->enable(name);
389                }
390                ftDump->mUnderruns = underruns;
391                ftDump->mFramesReady = framesReady;
392            }
393            // process() is CPU-bound
394            mixer->process(AudioBufferProvider::kInvalidPTS);
395            mixBufferState = MIXED;
396        } else if (mixBufferState == MIXED) {
397            mixBufferState = UNDEFINED;
398        }
399        bool attemptedWrite = false;
400        //bool didFullWrite = false;    // dumpsys could display a count of partial writes
401        if ((command & FastMixerState::WRITE) && (outputSink != NULL) && (mixBuffer != NULL)) {
402            if (mixBufferState == UNDEFINED) {
403                memset(mixBuffer, 0, frameCount * 2 * sizeof(short));
404                mixBufferState = ZEROED;
405            }
406            if (teeSink != NULL) {
407                (void) teeSink->write(mixBuffer, frameCount);
408            }
409            // FIXME write() is non-blocking and lock-free for a properly implemented NBAIO sink,
410            //       but this code should be modified to handle both non-blocking and blocking sinks
411            dumpState->mWriteSequence++;
412#if defined(ATRACE_TAG) && (ATRACE_TAG != ATRACE_TAG_NEVER)
413            Tracer::traceBegin(ATRACE_TAG, "write");
414#endif
415            ssize_t framesWritten = outputSink->write(mixBuffer, frameCount);
416#if defined(ATRACE_TAG) && (ATRACE_TAG != ATRACE_TAG_NEVER)
417            Tracer::traceEnd(ATRACE_TAG);
418#endif
419            dumpState->mWriteSequence++;
420            if (framesWritten >= 0) {
421                ALOG_ASSERT(framesWritten <= frameCount);
422                dumpState->mFramesWritten += framesWritten;
423                //if ((size_t) framesWritten == frameCount) {
424                //    didFullWrite = true;
425                //}
426            } else {
427                dumpState->mWriteErrors++;
428            }
429            attemptedWrite = true;
430            // FIXME count # of writes blocked excessively, CPU usage, etc. for dump
431        }
432
433        // To be exactly periodic, compute the next sleep time based on current time.
434        // This code doesn't have long-term stability when the sink is non-blocking.
435        // FIXME To avoid drift, use the local audio clock or watch the sink's fill status.
436        struct timespec newTs;
437        int rc = clock_gettime(CLOCK_MONOTONIC, &newTs);
438        if (rc == 0) {
439            if (oldTsValid) {
440                time_t sec = newTs.tv_sec - oldTs.tv_sec;
441                long nsec = newTs.tv_nsec - oldTs.tv_nsec;
442                if (nsec < 0) {
443                    --sec;
444                    nsec += 1000000000;
445                }
446                // To avoid an initial underrun on fast tracks after exiting standby,
447                // do not start pulling data from tracks and mixing until warmup is complete.
448                // Warmup is considered complete after the earlier of:
449                //      first successful single write() that blocks for more than warmupNs
450                //      MAX_WARMUP_CYCLES write() attempts.
451                // This is overly conservative, but to get better accuracy requires a new HAL API.
452                if (!isWarm && attemptedWrite) {
453                    measuredWarmupTs.tv_sec += sec;
454                    measuredWarmupTs.tv_nsec += nsec;
455                    if (measuredWarmupTs.tv_nsec >= 1000000000) {
456                        measuredWarmupTs.tv_sec++;
457                        measuredWarmupTs.tv_nsec -= 1000000000;
458                    }
459                    ++warmupCycles;
460                    if ((attemptedWrite && nsec > warmupNs) ||
461                            (warmupCycles >= MAX_WARMUP_CYCLES)) {
462                        isWarm = true;
463                        dumpState->mMeasuredWarmupTs = measuredWarmupTs;
464                        dumpState->mWarmupCycles = warmupCycles;
465                    }
466                }
467                if (sec > 0 || nsec > underrunNs) {
468#if defined(ATRACE_TAG) && (ATRACE_TAG != ATRACE_TAG_NEVER)
469                    ScopedTrace st(ATRACE_TAG, "underrun");
470#endif
471                    // FIXME only log occasionally
472                    ALOGV("underrun: time since last cycle %d.%03ld sec",
473                            (int) sec, nsec / 1000000L);
474                    dumpState->mUnderruns++;
475                    sleepNs = -1;
476                    ignoreNextOverrun = true;
477                } else if (nsec < overrunNs) {
478                    if (ignoreNextOverrun) {
479                        ignoreNextOverrun = false;
480                    } else {
481                        // FIXME only log occasionally
482                        ALOGV("overrun: time since last cycle %d.%03ld sec",
483                                (int) sec, nsec / 1000000L);
484                        dumpState->mOverruns++;
485                    }
486                    sleepNs = periodNs - overrunNs;
487                } else {
488                    sleepNs = -1;
489                    ignoreNextOverrun = false;
490                }
491#ifdef FAST_MIXER_STATISTICS
492                // advance the FIFO queue bounds
493                size_t i = bounds & (FastMixerDumpState::kSamplingN - 1);
494                bounds = (bounds & 0xFFFF0000) | ((bounds + 1) & 0xFFFF);
495                if (full) {
496                    bounds += 0x10000;
497                } else if (!(bounds & (FastMixerDumpState::kSamplingN - 1))) {
498                    full = true;
499                }
500                // compute the delta value of clock_gettime(CLOCK_MONOTONIC)
501                uint32_t monotonicNs = nsec;
502                if (sec > 0 && sec < 4) {
503                    monotonicNs += sec * 1000000000;
504                }
505                // compute the raw CPU load = delta value of clock_gettime(CLOCK_THREAD_CPUTIME_ID)
506                uint32_t loadNs = 0;
507                struct timespec newLoad;
508                rc = clock_gettime(CLOCK_THREAD_CPUTIME_ID, &newLoad);
509                if (rc == 0) {
510                    if (oldLoadValid) {
511                        sec = newLoad.tv_sec - oldLoad.tv_sec;
512                        nsec = newLoad.tv_nsec - oldLoad.tv_nsec;
513                        if (nsec < 0) {
514                            --sec;
515                            nsec += 1000000000;
516                        }
517                        loadNs = nsec;
518                        if (sec > 0 && sec < 4) {
519                            loadNs += sec * 1000000000;
520                        }
521                    } else {
522                        // first time through the loop
523                        oldLoadValid = true;
524                    }
525                    oldLoad = newLoad;
526                }
527                // get the absolute value of CPU clock frequency in kHz
528                int cpuNum = sched_getcpu();
529                uint32_t kHz = tcu.getCpukHz(cpuNum);
530                kHz = (kHz << 4) | (cpuNum & 0xF);
531                // save values in FIFO queues for dumpsys
532                // these stores #1, #2, #3 are not atomic with respect to each other,
533                // or with respect to store #4 below
534                dumpState->mMonotonicNs[i] = monotonicNs;
535                dumpState->mLoadNs[i] = loadNs;
536                dumpState->mCpukHz[i] = kHz;
537                // this store #4 is not atomic with respect to stores #1, #2, #3 above, but
538                // the newest open and oldest closed halves are atomic with respect to each other
539                dumpState->mBounds = bounds;
540#if defined(ATRACE_TAG) && (ATRACE_TAG != ATRACE_TAG_NEVER)
541                ATRACE_INT("cycle_ms", monotonicNs / 1000000);
542                ATRACE_INT("load_us", loadNs / 1000);
543#endif
544#endif
545            } else {
546                // first time through the loop
547                oldTsValid = true;
548                sleepNs = periodNs;
549                ignoreNextOverrun = true;
550            }
551            oldTs = newTs;
552        } else {
553            // monotonic clock is broken
554            oldTsValid = false;
555            sleepNs = periodNs;
556        }
557
558
559    }   // for (;;)
560
561    // never return 'true'; Thread::_threadLoop() locks mutex which can result in priority inversion
562}
563
564FastMixerDumpState::FastMixerDumpState() :
565    mCommand(FastMixerState::INITIAL), mWriteSequence(0), mFramesWritten(0),
566    mNumTracks(0), mWriteErrors(0), mUnderruns(0), mOverruns(0),
567    mSampleRate(0), mFrameCount(0), /* mMeasuredWarmupTs({0, 0}), */ mWarmupCycles(0),
568    mTrackMask(0)
569#ifdef FAST_MIXER_STATISTICS
570    , mBounds(0)
571#endif
572{
573    mMeasuredWarmupTs.tv_sec = 0;
574    mMeasuredWarmupTs.tv_nsec = 0;
575    // sample arrays aren't accessed atomically with respect to the bounds,
576    // so clearing reduces chance for dumpsys to read random uninitialized samples
577    memset(&mMonotonicNs, 0, sizeof(mMonotonicNs));
578    memset(&mLoadNs, 0, sizeof(mLoadNs));
579    memset(&mCpukHz, 0, sizeof(mCpukHz));
580}
581
582FastMixerDumpState::~FastMixerDumpState()
583{
584}
585
586void FastMixerDumpState::dump(int fd)
587{
588#define COMMAND_MAX 32
589    char string[COMMAND_MAX];
590    switch (mCommand) {
591    case FastMixerState::INITIAL:
592        strcpy(string, "INITIAL");
593        break;
594    case FastMixerState::HOT_IDLE:
595        strcpy(string, "HOT_IDLE");
596        break;
597    case FastMixerState::COLD_IDLE:
598        strcpy(string, "COLD_IDLE");
599        break;
600    case FastMixerState::EXIT:
601        strcpy(string, "EXIT");
602        break;
603    case FastMixerState::MIX:
604        strcpy(string, "MIX");
605        break;
606    case FastMixerState::WRITE:
607        strcpy(string, "WRITE");
608        break;
609    case FastMixerState::MIX_WRITE:
610        strcpy(string, "MIX_WRITE");
611        break;
612    default:
613        snprintf(string, COMMAND_MAX, "%d", mCommand);
614        break;
615    }
616    double measuredWarmupMs = (mMeasuredWarmupTs.tv_sec * 1000.0) +
617            (mMeasuredWarmupTs.tv_nsec / 1000000.0);
618    double mixPeriodSec = (double) mFrameCount / (double) mSampleRate;
619    fdprintf(fd, "FastMixer command=%s writeSequence=%u framesWritten=%u\n"
620                 "          numTracks=%u writeErrors=%u underruns=%u overruns=%u\n"
621                 "          sampleRate=%u frameCount=%u measuredWarmup=%.3g ms, warmupCycles=%u\n"
622                 "          mixPeriod=%.2f ms\n",
623                 string, mWriteSequence, mFramesWritten,
624                 mNumTracks, mWriteErrors, mUnderruns, mOverruns,
625                 mSampleRate, mFrameCount, measuredWarmupMs, mWarmupCycles,
626                 mixPeriodSec * 1e3);
627#ifdef FAST_MIXER_STATISTICS
628    // find the interval of valid samples
629    uint32_t bounds = mBounds;
630    uint32_t newestOpen = bounds & 0xFFFF;
631    uint32_t oldestClosed = bounds >> 16;
632    uint32_t n = (newestOpen - oldestClosed) & 0xFFFF;
633    if (n > kSamplingN) {
634        ALOGE("too many samples %u", n);
635        n = kSamplingN;
636    }
637    // statistics for monotonic (wall clock) time, thread raw CPU load in time, CPU clock frequency,
638    // and adjusted CPU load in MHz normalized for CPU clock frequency
639    CentralTendencyStatistics wall, loadNs, kHz, loadMHz;
640    // only compute adjusted CPU load in Hz if current CPU number and CPU clock frequency are stable
641    bool valid = false;
642    uint32_t previousCpukHz = 0;
643    // loop over all the samples
644    for (; n > 0; --n) {
645        size_t i = oldestClosed++ & (kSamplingN - 1);
646        uint32_t wallNs = mMonotonicNs[i];
647        wall.sample(wallNs);
648        uint32_t sampleLoadNs = mLoadNs[i];
649        uint32_t sampleCpukHz = mCpukHz[i];
650        loadNs.sample(sampleLoadNs);
651        // skip bad kHz samples
652        if ((sampleCpukHz & ~0xF) != 0) {
653            kHz.sample(sampleCpukHz >> 4);
654            if (sampleCpukHz == previousCpukHz) {
655                double megacycles = (double) sampleLoadNs * (double) (sampleCpukHz >> 4) * 1e-12;
656                double adjMHz = megacycles / mixPeriodSec;  // _not_ wallNs * 1e9
657                loadMHz.sample(adjMHz);
658            }
659        }
660        previousCpukHz = sampleCpukHz;
661    }
662    fdprintf(fd, "Simple moving statistics over last %.1f seconds:\n", wall.n() * mixPeriodSec);
663    fdprintf(fd, "  wall clock time in ms per mix cycle:\n"
664                 "    mean=%.2f min=%.2f max=%.2f stddev=%.2f\n",
665                 wall.mean()*1e-6, wall.minimum()*1e-6, wall.maximum()*1e-6, wall.stddev()*1e-6);
666    fdprintf(fd, "  raw CPU load in us per mix cycle:\n"
667                 "    mean=%.0f min=%.0f max=%.0f stddev=%.0f\n",
668                 loadNs.mean()*1e-3, loadNs.minimum()*1e-3, loadNs.maximum()*1e-3,
669                 loadNs.stddev()*1e-3);
670    fdprintf(fd, "  CPU clock frequency in MHz:\n"
671                 "    mean=%.0f min=%.0f max=%.0f stddev=%.0f\n",
672                 kHz.mean()*1e-3, kHz.minimum()*1e-3, kHz.maximum()*1e-3, kHz.stddev()*1e-3);
673    fdprintf(fd, "  adjusted CPU load in MHz (i.e. normalized for CPU clock frequency):\n"
674                 "    mean=%.1f min=%.1f max=%.1f stddev=%.1f\n",
675                 loadMHz.mean(), loadMHz.minimum(), loadMHz.maximum(), loadMHz.stddev());
676#endif
677    // The active track mask and track states are updated non-atomically.
678    // So if we relied on isActive to decide whether to display,
679    // then we might display an obsolete track or omit an active track.
680    // Instead we always display all tracks, with an indication
681    // of whether we think the track is active.
682    uint32_t trackMask = mTrackMask;
683    fdprintf(fd, "Fast tracks: kMaxFastTracks=%u activeMask=%#x\n",
684            FastMixerState::kMaxFastTracks, trackMask);
685    fdprintf(fd, "Index Active Full Partial Empty  Recent Ready\n");
686    for (uint32_t i = 0; i < FastMixerState::kMaxFastTracks; ++i, trackMask >>= 1) {
687        bool isActive = trackMask & 1;
688        const FastTrackDump *ftDump = &mTracks[i];
689        const FastTrackUnderruns& underruns = ftDump->mUnderruns;
690        const char *mostRecent;
691        switch (underruns.mBitFields.mMostRecent) {
692        case UNDERRUN_FULL:
693            mostRecent = "full";
694            break;
695        case UNDERRUN_PARTIAL:
696            mostRecent = "partial";
697            break;
698        case UNDERRUN_EMPTY:
699            mostRecent = "empty";
700            break;
701        default:
702            mostRecent = "?";
703            break;
704        }
705        fdprintf(fd, "%5u %6s %4u %7u %5u %7s %5u\n", i, isActive ? "yes" : "no",
706                (underruns.mBitFields.mFull) & UNDERRUN_MASK,
707                (underruns.mBitFields.mPartial) & UNDERRUN_MASK,
708                (underruns.mBitFields.mEmpty) & UNDERRUN_MASK,
709                mostRecent, ftDump->mFramesReady);
710    }
711}
712
713}   // namespace android
714