/*
* Copyright (C) 2013 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 ATRACE_TAG ATRACE_TAG_GRAPHICS
//#define LOG_NDEBUG 0
// This is needed for stdint.h to define INT64_MAX in C++
#define __STDC_LIMIT_MACROS
#include <math.h>
#include <algorithm>
#include <android-base/stringprintf.h>
#include <cutils/properties.h>
#include <log/log.h>
#include <utils/Thread.h>
#include <utils/Trace.h>
#include <ui/FenceTime.h>
#include "DispSync.h"
#include "EventLog/EventLog.h"
#include "SurfaceFlinger.h"
using android::base::StringAppendF;
using std::max;
using std::min;
namespace android {
DispSync::~DispSync() = default;
DispSync::Callback::~Callback() = default;
namespace impl {
// Setting this to true adds a zero-phase tracer for correlating with hardware
// vsync events
static const bool kEnableZeroPhaseTracer = false;
// This is the threshold used to determine when hardware vsync events are
// needed to re-synchronize the software vsync model with the hardware. The
// error metric used is the mean of the squared difference between each
// present time and the nearest software-predicted vsync.
static const nsecs_t kErrorThreshold = 160000000000; // 400 usec squared
#undef LOG_TAG
#define LOG_TAG "DispSyncThread"
class DispSyncThread : public Thread {
public:
DispSyncThread(const char* name, bool showTraceDetailedInfo)
: mName(name),
mStop(false),
mModelLocked(false),
mPeriod(0),
mPhase(0),
mReferenceTime(0),
mWakeupLatency(0),
mFrameNumber(0),
mTraceDetailedInfo(showTraceDetailedInfo) {}
virtual ~DispSyncThread() {}
void updateModel(nsecs_t period, nsecs_t phase, nsecs_t referenceTime) {
if (mTraceDetailedInfo) ATRACE_CALL();
Mutex::Autolock lock(mMutex);
mPhase = phase;
if (mReferenceTime != referenceTime) {
for (auto& eventListener : mEventListeners) {
eventListener.mHasFired = false;
}
}
mReferenceTime = referenceTime;
if (mPeriod != 0 && mPeriod != period && mReferenceTime != 0) {
// Inflate the reference time to be the most recent predicted
// vsync before the current time.
const nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
const nsecs_t baseTime = now - mReferenceTime;
const nsecs_t numOldPeriods = baseTime / mPeriod;
mReferenceTime = mReferenceTime + (numOldPeriods)*mPeriod;
}
mPeriod = period;
if (mTraceDetailedInfo) {
ATRACE_INT64("DispSync:Period", mPeriod);
ATRACE_INT64("DispSync:Phase", mPhase + mPeriod / 2);
ATRACE_INT64("DispSync:Reference Time", mReferenceTime);
}
ALOGV("[%s] updateModel: mPeriod = %" PRId64 ", mPhase = %" PRId64
" mReferenceTime = %" PRId64,
mName, ns2us(mPeriod), ns2us(mPhase), ns2us(mReferenceTime));
mCond.signal();
}
void stop() {
if (mTraceDetailedInfo) ATRACE_CALL();
Mutex::Autolock lock(mMutex);
mStop = true;
mCond.signal();
}
void lockModel() {
Mutex::Autolock lock(mMutex);
mModelLocked = true;
}
void unlockModel() {
Mutex::Autolock lock(mMutex);
mModelLocked = false;
}
virtual bool threadLoop() {
status_t err;
nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
while (true) {
std::vector<CallbackInvocation> callbackInvocations;
nsecs_t targetTime = 0;
{ // Scope for lock
Mutex::Autolock lock(mMutex);
if (mTraceDetailedInfo) {
ATRACE_INT64("DispSync:Frame", mFrameNumber);
}
ALOGV("[%s] Frame %" PRId64, mName, mFrameNumber);
++mFrameNumber;
if (mStop) {
return false;
}
if (mPeriod == 0) {
err = mCond.wait(mMutex);
if (err != NO_ERROR) {
ALOGE("error waiting for new events: %s (%d)", strerror(-err), err);
return false;
}
continue;
}
targetTime = computeNextEventTimeLocked(now);
bool isWakeup = false;
if (now < targetTime) {
if (mTraceDetailedInfo) ATRACE_NAME("DispSync waiting");
if (targetTime == INT64_MAX) {
ALOGV("[%s] Waiting forever", mName);
err = mCond.wait(mMutex);
} else {
ALOGV("[%s] Waiting until %" PRId64, mName, ns2us(targetTime));
err = mCond.waitRelative(mMutex, targetTime - now);
}
if (err == TIMED_OUT) {
isWakeup = true;
} else if (err != NO_ERROR) {
ALOGE("error waiting for next event: %s (%d)", strerror(-err), err);
return false;
}
}
now = systemTime(SYSTEM_TIME_MONOTONIC);
// Don't correct by more than 1.5 ms
static const nsecs_t kMaxWakeupLatency = us2ns(1500);
if (isWakeup) {
mWakeupLatency = ((mWakeupLatency * 63) + (now - targetTime)) / 64;
mWakeupLatency = min(mWakeupLatency, kMaxWakeupLatency);
if (mTraceDetailedInfo) {
ATRACE_INT64("DispSync:WakeupLat", now - targetTime);
ATRACE_INT64("DispSync:AvgWakeupLat", mWakeupLatency);
}
}
callbackInvocations = gatherCallbackInvocationsLocked(now);
}
if (callbackInvocations.size() > 0) {
fireCallbackInvocations(callbackInvocations);
}
}
return false;
}
status_t addEventListener(const char* name, nsecs_t phase, DispSync::Callback* callback,
nsecs_t lastCallbackTime) {
if (mTraceDetailedInfo) ATRACE_CALL();
Mutex::Autolock lock(mMutex);
for (size_t i = 0; i < mEventListeners.size(); i++) {
if (mEventListeners[i].mCallback == callback) {
return BAD_VALUE;
}
}
EventListener listener;
listener.mName = name;
listener.mPhase = phase;
listener.mCallback = callback;
// We want to allow the firstmost future event to fire without
// allowing any past events to fire. To do this extrapolate from
// mReferenceTime the most recent hardware vsync, and pin the
// last event time there.
const nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
if (mPeriod != 0) {
const nsecs_t baseTime = now - mReferenceTime;
const nsecs_t numPeriodsSinceReference = baseTime / mPeriod;
const nsecs_t predictedReference = mReferenceTime + numPeriodsSinceReference * mPeriod;
const nsecs_t phaseCorrection = mPhase + listener.mPhase;
const nsecs_t predictedLastEventTime = predictedReference + phaseCorrection;
if (predictedLastEventTime >= now) {
// Make sure that the last event time does not exceed the current time.
// If it would, then back the last event time by a period.
listener.mLastEventTime = predictedLastEventTime - mPeriod;
} else {
listener.mLastEventTime = predictedLastEventTime;
}
} else {
listener.mLastEventTime = now + mPhase - mWakeupLatency;
}
if (lastCallbackTime <= 0) {
// If there is no prior callback time, try to infer one based on the
// logical last event time.
listener.mLastCallbackTime = listener.mLastEventTime + mWakeupLatency;
} else {
listener.mLastCallbackTime = lastCallbackTime;
}
mEventListeners.push_back(listener);
mCond.signal();
return NO_ERROR;
}
status_t removeEventListener(DispSync::Callback* callback, nsecs_t* outLastCallback) {
if (mTraceDetailedInfo) ATRACE_CALL();
Mutex::Autolock lock(mMutex);
for (std::vector<EventListener>::iterator it = mEventListeners.begin();
it != mEventListeners.end(); ++it) {
if (it->mCallback == callback) {
*outLastCallback = it->mLastCallbackTime;
mEventListeners.erase(it);
mCond.signal();
return NO_ERROR;
}
}
return BAD_VALUE;
}
status_t changePhaseOffset(DispSync::Callback* callback, nsecs_t phase) {
if (mTraceDetailedInfo) ATRACE_CALL();
Mutex::Autolock lock(mMutex);
for (auto& eventListener : mEventListeners) {
if (eventListener.mCallback == callback) {
const nsecs_t oldPhase = eventListener.mPhase;
eventListener.mPhase = phase;
// Pretend that the last time this event was handled at the same frame but with the
// new offset to allow for a seamless offset change without double-firing or
// skipping.
nsecs_t diff = oldPhase - phase;
if (diff > mPeriod / 2) {
diff -= mPeriod;
} else if (diff < -mPeriod / 2) {
diff += mPeriod;
}
eventListener.mLastEventTime -= diff;
mCond.signal();
return NO_ERROR;
}
}
return BAD_VALUE;
}
private:
struct EventListener {
const char* mName;
nsecs_t mPhase;
nsecs_t mLastEventTime;
nsecs_t mLastCallbackTime;
DispSync::Callback* mCallback;
bool mHasFired = false;
};
struct CallbackInvocation {
DispSync::Callback* mCallback;
nsecs_t mEventTime;
};
nsecs_t computeNextEventTimeLocked(nsecs_t now) {
if (mTraceDetailedInfo) ATRACE_CALL();
ALOGV("[%s] computeNextEventTimeLocked", mName);
nsecs_t nextEventTime = INT64_MAX;
for (size_t i = 0; i < mEventListeners.size(); i++) {
nsecs_t t = computeListenerNextEventTimeLocked(mEventListeners[i], now);
if (t < nextEventTime) {
nextEventTime = t;
}
}
ALOGV("[%s] nextEventTime = %" PRId64, mName, ns2us(nextEventTime));
return nextEventTime;
}
// Sanity check that the duration is close enough in length to a period without
// falling into double-rate vsyncs.
bool isCloseToPeriod(nsecs_t duration) {
// Ratio of 3/5 is arbitrary, but it must be greater than 1/2.
return duration < (3 * mPeriod) / 5;
}
std::vector<CallbackInvocation> gatherCallbackInvocationsLocked(nsecs_t now) {
if (mTraceDetailedInfo) ATRACE_CALL();
ALOGV("[%s] gatherCallbackInvocationsLocked @ %" PRId64, mName, ns2us(now));
std::vector<CallbackInvocation> callbackInvocations;
nsecs_t onePeriodAgo = now - mPeriod;
for (auto& eventListener : mEventListeners) {
nsecs_t t = computeListenerNextEventTimeLocked(eventListener, onePeriodAgo);
if (t < now) {
if (isCloseToPeriod(now - eventListener.mLastCallbackTime)) {
eventListener.mLastEventTime = t;
ALOGV("[%s] [%s] Skipping event due to model error", mName,
eventListener.mName);
continue;
}
if (eventListener.mHasFired && !mModelLocked) {
eventListener.mLastEventTime = t;
ALOGV("[%s] [%s] Skipping event due to already firing", mName,
eventListener.mName);
continue;
}
CallbackInvocation ci;
ci.mCallback = eventListener.mCallback;
ci.mEventTime = t;
ALOGV("[%s] [%s] Preparing to fire, latency: %" PRId64, mName, eventListener.mName,
t - eventListener.mLastEventTime);
callbackInvocations.push_back(ci);
eventListener.mLastEventTime = t;
eventListener.mLastCallbackTime = now;
eventListener.mHasFired = true;
}
}
return callbackInvocations;
}
nsecs_t computeListenerNextEventTimeLocked(const EventListener& listener, nsecs_t baseTime) {
if (mTraceDetailedInfo) ATRACE_CALL();
ALOGV("[%s] [%s] computeListenerNextEventTimeLocked(%" PRId64 ")", mName, listener.mName,
ns2us(baseTime));
nsecs_t lastEventTime = listener.mLastEventTime + mWakeupLatency;
ALOGV("[%s] lastEventTime: %" PRId64, mName, ns2us(lastEventTime));
if (baseTime < lastEventTime) {
baseTime = lastEventTime;
ALOGV("[%s] Clamping baseTime to lastEventTime -> %" PRId64, mName, ns2us(baseTime));
}
baseTime -= mReferenceTime;
ALOGV("[%s] Relative baseTime = %" PRId64, mName, ns2us(baseTime));
nsecs_t phase = mPhase + listener.mPhase;
ALOGV("[%s] Phase = %" PRId64, mName, ns2us(phase));
baseTime -= phase;
ALOGV("[%s] baseTime - phase = %" PRId64, mName, ns2us(baseTime));
// If our previous time is before the reference (because the reference
// has since been updated), the division by mPeriod will truncate
// towards zero instead of computing the floor. Since in all cases
// before the reference we want the next time to be effectively now, we
// set baseTime to -mPeriod so that numPeriods will be -1.
// When we add 1 and the phase, we will be at the correct event time for
// this period.
if (baseTime < 0) {
ALOGV("[%s] Correcting negative baseTime", mName);
baseTime = -mPeriod;
}
nsecs_t numPeriods = baseTime / mPeriod;
ALOGV("[%s] numPeriods = %" PRId64, mName, numPeriods);
nsecs_t t = (numPeriods + 1) * mPeriod + phase;
ALOGV("[%s] t = %" PRId64, mName, ns2us(t));
t += mReferenceTime;
ALOGV("[%s] Absolute t = %" PRId64, mName, ns2us(t));
// Check that it's been slightly more than half a period since the last
// event so that we don't accidentally fall into double-rate vsyncs
if (isCloseToPeriod(t - listener.mLastEventTime)) {
t += mPeriod;
ALOGV("[%s] Modifying t -> %" PRId64, mName, ns2us(t));
}
t -= mWakeupLatency;
ALOGV("[%s] Corrected for wakeup latency -> %" PRId64, mName, ns2us(t));
return t;
}
void fireCallbackInvocations(const std::vector<CallbackInvocation>& callbacks) {
if (mTraceDetailedInfo) ATRACE_CALL();
for (size_t i = 0; i < callbacks.size(); i++) {
callbacks[i].mCallback->onDispSyncEvent(callbacks[i].mEventTime);
}
}
const char* const mName;
bool mStop;
bool mModelLocked;
nsecs_t mPeriod;
nsecs_t mPhase;
nsecs_t mReferenceTime;
nsecs_t mWakeupLatency;
int64_t mFrameNumber;
std::vector<EventListener> mEventListeners;
Mutex mMutex;
Condition mCond;
// Flag to turn on logging in systrace.
const bool mTraceDetailedInfo;
};
#undef LOG_TAG
#define LOG_TAG "DispSync"
class ZeroPhaseTracer : public DispSync::Callback {
public:
ZeroPhaseTracer() : mParity(false) {}
virtual void onDispSyncEvent(nsecs_t /*when*/) {
mParity = !mParity;
ATRACE_INT("ZERO_PHASE_VSYNC", mParity ? 1 : 0);
}
private:
bool mParity;
};
DispSync::DispSync(const char* name) : mName(name), mRefreshSkipCount(0) {
// This flag offers the ability to turn on systrace logging from the shell.
char value[PROPERTY_VALUE_MAX];
property_get("debug.sf.dispsync_trace_detailed_info", value, "0");
mTraceDetailedInfo = atoi(value);
mThread = new DispSyncThread(name, mTraceDetailedInfo);
}
DispSync::~DispSync() {
mThread->stop();
mThread->requestExitAndWait();
}
void DispSync::init(bool hasSyncFramework, int64_t dispSyncPresentTimeOffset) {
mIgnorePresentFences = !hasSyncFramework;
mPresentTimeOffset = dispSyncPresentTimeOffset;
mThread->run("DispSync", PRIORITY_URGENT_DISPLAY + PRIORITY_MORE_FAVORABLE);
// set DispSync to SCHED_FIFO to minimize jitter
struct sched_param param = {0};
param.sched_priority = 2;
if (sched_setscheduler(mThread->getTid(), SCHED_FIFO, ¶m) != 0) {
ALOGE("Couldn't set SCHED_FIFO for DispSyncThread");
}
reset();
beginResync();
if (mTraceDetailedInfo && kEnableZeroPhaseTracer) {
mZeroPhaseTracer = std::make_unique<ZeroPhaseTracer>();
addEventListener("ZeroPhaseTracer", 0, mZeroPhaseTracer.get(), 0);
}
}
void DispSync::reset() {
Mutex::Autolock lock(mMutex);
resetLocked();
}
void DispSync::resetLocked() {
mPhase = 0;
const size_t lastSampleIdx = (mFirstResyncSample + mNumResyncSamples - 1) % MAX_RESYNC_SAMPLES;
// Keep the most recent sample, when we resync to hardware we'll overwrite this
// with a more accurate signal
if (mResyncSamples[lastSampleIdx] != 0) {
mReferenceTime = mResyncSamples[lastSampleIdx];
}
mModelUpdated = false;
for (size_t i = 0; i < MAX_RESYNC_SAMPLES; i++) {
mResyncSamples[i] = 0;
}
mNumResyncSamples = 0;
mFirstResyncSample = 0;
mNumResyncSamplesSincePresent = 0;
mThread->unlockModel();
resetErrorLocked();
}
bool DispSync::addPresentFence(const std::shared_ptr<FenceTime>& fenceTime) {
Mutex::Autolock lock(mMutex);
if (mIgnorePresentFences) {
return true;
}
mPresentFences[mPresentSampleOffset] = fenceTime;
mPresentSampleOffset = (mPresentSampleOffset + 1) % NUM_PRESENT_SAMPLES;
mNumResyncSamplesSincePresent = 0;
updateErrorLocked();
return !mModelUpdated || mError > kErrorThreshold;
}
void DispSync::beginResync() {
Mutex::Autolock lock(mMutex);
ALOGV("[%s] beginResync", mName);
mThread->unlockModel();
mModelUpdated = false;
mNumResyncSamples = 0;
}
bool DispSync::addResyncSample(nsecs_t timestamp, bool* periodChanged) {
Mutex::Autolock lock(mMutex);
ALOGV("[%s] addResyncSample(%" PRId64 ")", mName, ns2us(timestamp));
*periodChanged = false;
const size_t idx = (mFirstResyncSample + mNumResyncSamples) % MAX_RESYNC_SAMPLES;
mResyncSamples[idx] = timestamp;
if (mNumResyncSamples == 0) {
mPhase = 0;
ALOGV("[%s] First resync sample: mPeriod = %" PRId64 ", mPhase = 0, "
"mReferenceTime = %" PRId64,
mName, ns2us(mPeriod), ns2us(timestamp));
} else if (mPendingPeriod > 0) {
// mNumResyncSamples > 0, so priorIdx won't overflow
const size_t priorIdx = (mFirstResyncSample + mNumResyncSamples - 1) % MAX_RESYNC_SAMPLES;
const nsecs_t lastTimestamp = mResyncSamples[priorIdx];
const nsecs_t observedVsync = std::abs(timestamp - lastTimestamp);
if (std::abs(observedVsync - mPendingPeriod) < std::abs(observedVsync - mPeriod)) {
// Observed vsync is closer to the pending period, so reset the
// model and flush the pending period.
resetLocked();
mPeriod = mPendingPeriod;
mPendingPeriod = 0;
if (mTraceDetailedInfo) {
ATRACE_INT("DispSync:PendingPeriod", mPendingPeriod);
}
*periodChanged = true;
}
}
// Always update the reference time with the most recent timestamp.
mReferenceTime = timestamp;
mThread->updateModel(mPeriod, mPhase, mReferenceTime);
if (mNumResyncSamples < MAX_RESYNC_SAMPLES) {
mNumResyncSamples++;
} else {
mFirstResyncSample = (mFirstResyncSample + 1) % MAX_RESYNC_SAMPLES;
}
updateModelLocked();
if (mNumResyncSamplesSincePresent++ > MAX_RESYNC_SAMPLES_WITHOUT_PRESENT) {
resetErrorLocked();
}
if (mIgnorePresentFences) {
// If we're ignoring the present fences we have no way to know whether
// or not we're synchronized with the HW vsyncs, so we just request
// that the HW vsync events be turned on.
return true;
}
// Check against kErrorThreshold / 2 to add some hysteresis before having to
// resync again
bool modelLocked = mModelUpdated && mError < (kErrorThreshold / 2) && mPendingPeriod == 0;
ALOGV("[%s] addResyncSample returning %s", mName, modelLocked ? "locked" : "unlocked");
if (modelLocked) {
mThread->lockModel();
}
return !modelLocked;
}
void DispSync::endResync() {
mThread->lockModel();
}
status_t DispSync::addEventListener(const char* name, nsecs_t phase, Callback* callback,
nsecs_t lastCallbackTime) {
Mutex::Autolock lock(mMutex);
return mThread->addEventListener(name, phase, callback, lastCallbackTime);
}
void DispSync::setRefreshSkipCount(int count) {
Mutex::Autolock lock(mMutex);
ALOGD("setRefreshSkipCount(%d)", count);
mRefreshSkipCount = count;
updateModelLocked();
}
status_t DispSync::removeEventListener(Callback* callback, nsecs_t* outLastCallbackTime) {
Mutex::Autolock lock(mMutex);
return mThread->removeEventListener(callback, outLastCallbackTime);
}
status_t DispSync::changePhaseOffset(Callback* callback, nsecs_t phase) {
Mutex::Autolock lock(mMutex);
return mThread->changePhaseOffset(callback, phase);
}
void DispSync::setPeriod(nsecs_t period) {
Mutex::Autolock lock(mMutex);
if (mTraceDetailedInfo) {
ATRACE_INT("DispSync:PendingPeriod", period);
}
mPendingPeriod = period;
}
nsecs_t DispSync::getPeriod() {
// lock mutex as mPeriod changes multiple times in updateModelLocked
Mutex::Autolock lock(mMutex);
return mPeriod;
}
void DispSync::updateModelLocked() {
ALOGV("[%s] updateModelLocked %zu", mName, mNumResyncSamples);
if (mNumResyncSamples >= MIN_RESYNC_SAMPLES_FOR_UPDATE) {
ALOGV("[%s] Computing...", mName);
nsecs_t durationSum = 0;
nsecs_t minDuration = INT64_MAX;
nsecs_t maxDuration = 0;
for (size_t i = 1; i < mNumResyncSamples; i++) {
size_t idx = (mFirstResyncSample + i) % MAX_RESYNC_SAMPLES;
size_t prev = (idx + MAX_RESYNC_SAMPLES - 1) % MAX_RESYNC_SAMPLES;
nsecs_t duration = mResyncSamples[idx] - mResyncSamples[prev];
durationSum += duration;
minDuration = min(minDuration, duration);
maxDuration = max(maxDuration, duration);
}
// Exclude the min and max from the average
durationSum -= minDuration + maxDuration;
mPeriod = durationSum / (mNumResyncSamples - 3);
ALOGV("[%s] mPeriod = %" PRId64, mName, ns2us(mPeriod));
double sampleAvgX = 0;
double sampleAvgY = 0;
double scale = 2.0 * M_PI / double(mPeriod);
// Intentionally skip the first sample
for (size_t i = 1; i < mNumResyncSamples; i++) {
size_t idx = (mFirstResyncSample + i) % MAX_RESYNC_SAMPLES;
nsecs_t sample = mResyncSamples[idx] - mReferenceTime;
double samplePhase = double(sample % mPeriod) * scale;
sampleAvgX += cos(samplePhase);
sampleAvgY += sin(samplePhase);
}
sampleAvgX /= double(mNumResyncSamples - 1);
sampleAvgY /= double(mNumResyncSamples - 1);
mPhase = nsecs_t(atan2(sampleAvgY, sampleAvgX) / scale);
ALOGV("[%s] mPhase = %" PRId64, mName, ns2us(mPhase));
if (mPhase < -(mPeriod / 2)) {
mPhase += mPeriod;
ALOGV("[%s] Adjusting mPhase -> %" PRId64, mName, ns2us(mPhase));
}
// Artificially inflate the period if requested.
mPeriod += mPeriod * mRefreshSkipCount;
mThread->updateModel(mPeriod, mPhase, mReferenceTime);
mModelUpdated = true;
}
}
void DispSync::updateErrorLocked() {
if (!mModelUpdated) {
return;
}
// Need to compare present fences against the un-adjusted refresh period,
// since they might arrive between two events.
nsecs_t period = mPeriod / (1 + mRefreshSkipCount);
int numErrSamples = 0;
nsecs_t sqErrSum = 0;
for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) {
// Only check for the cached value of signal time to avoid unecessary
// syscalls. It is the responsibility of the DispSync owner to
// call getSignalTime() periodically so the cache is updated when the
// fence signals.
nsecs_t time = mPresentFences[i]->getCachedSignalTime();
if (time == Fence::SIGNAL_TIME_PENDING || time == Fence::SIGNAL_TIME_INVALID) {
continue;
}
nsecs_t sample = time - mReferenceTime;
if (sample <= mPhase) {
continue;
}
nsecs_t sampleErr = (sample - mPhase) % period;
if (sampleErr > period / 2) {
sampleErr -= period;
}
sqErrSum += sampleErr * sampleErr;
numErrSamples++;
}
if (numErrSamples > 0) {
mError = sqErrSum / numErrSamples;
mZeroErrSamplesCount = 0;
} else {
mError = 0;
// Use mod ACCEPTABLE_ZERO_ERR_SAMPLES_COUNT to avoid log spam.
mZeroErrSamplesCount++;
ALOGE_IF((mZeroErrSamplesCount % ACCEPTABLE_ZERO_ERR_SAMPLES_COUNT) == 0,
"No present times for model error.");
}
if (mTraceDetailedInfo) {
ATRACE_INT64("DispSync:Error", mError);
}
}
void DispSync::resetErrorLocked() {
mPresentSampleOffset = 0;
mError = 0;
mZeroErrSamplesCount = 0;
for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) {
mPresentFences[i] = FenceTime::NO_FENCE;
}
}
nsecs_t DispSync::computeNextRefresh(int periodOffset) const {
Mutex::Autolock lock(mMutex);
nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
nsecs_t phase = mReferenceTime + mPhase;
if (mPeriod == 0) {
return 0;
}
return (((now - phase) / mPeriod) + periodOffset + 1) * mPeriod + phase;
}
void DispSync::setIgnorePresentFences(bool ignore) {
Mutex::Autolock lock(mMutex);
if (mIgnorePresentFences != ignore) {
mIgnorePresentFences = ignore;
resetLocked();
}
}
void DispSync::dump(std::string& result) const {
Mutex::Autolock lock(mMutex);
StringAppendF(&result, "present fences are %s\n", mIgnorePresentFences ? "ignored" : "used");
StringAppendF(&result, "mPeriod: %" PRId64 " ns (%.3f fps; skipCount=%d)\n", mPeriod,
1000000000.0 / mPeriod, mRefreshSkipCount);
StringAppendF(&result, "mPhase: %" PRId64 " ns\n", mPhase);
StringAppendF(&result, "mError: %" PRId64 " ns (sqrt=%.1f)\n", mError, sqrt(mError));
StringAppendF(&result, "mNumResyncSamplesSincePresent: %d (limit %d)\n",
mNumResyncSamplesSincePresent, MAX_RESYNC_SAMPLES_WITHOUT_PRESENT);
StringAppendF(&result, "mNumResyncSamples: %zd (max %d)\n", mNumResyncSamples,
MAX_RESYNC_SAMPLES);
result.append("mResyncSamples:\n");
nsecs_t previous = -1;
for (size_t i = 0; i < mNumResyncSamples; i++) {
size_t idx = (mFirstResyncSample + i) % MAX_RESYNC_SAMPLES;
nsecs_t sampleTime = mResyncSamples[idx];
if (i == 0) {
StringAppendF(&result, " %" PRId64 "\n", sampleTime);
} else {
StringAppendF(&result, " %" PRId64 " (+%" PRId64 ")\n", sampleTime,
sampleTime - previous);
}
previous = sampleTime;
}
StringAppendF(&result, "mPresentFences [%d]:\n", NUM_PRESENT_SAMPLES);
nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
previous = Fence::SIGNAL_TIME_INVALID;
for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) {
size_t idx = (i + mPresentSampleOffset) % NUM_PRESENT_SAMPLES;
nsecs_t presentTime = mPresentFences[idx]->getSignalTime();
if (presentTime == Fence::SIGNAL_TIME_PENDING) {
StringAppendF(&result, " [unsignaled fence]\n");
} else if (presentTime == Fence::SIGNAL_TIME_INVALID) {
StringAppendF(&result, " [invalid fence]\n");
} else if (previous == Fence::SIGNAL_TIME_PENDING ||
previous == Fence::SIGNAL_TIME_INVALID) {
StringAppendF(&result, " %" PRId64 " (%.3f ms ago)\n", presentTime,
(now - presentTime) / 1000000.0);
} else {
StringAppendF(&result, " %" PRId64 " (+%" PRId64 " / %.3f) (%.3f ms ago)\n",
presentTime, presentTime - previous,
(presentTime - previous) / (double)mPeriod,
(now - presentTime) / 1000000.0);
}
previous = presentTime;
}
StringAppendF(&result, "current monotonic time: %" PRId64 "\n", now);
}
nsecs_t DispSync::expectedPresentTime() {
// The HWC doesn't currently have a way to report additional latency.
// Assume that whatever we submit now will appear right after the flip.
// For a smart panel this might be 1. This is expressed in frames,
// rather than time, because we expect to have a constant frame delay
// regardless of the refresh rate.
const uint32_t hwcLatency = 0;
// Ask DispSync when the next refresh will be (CLOCK_MONOTONIC).
return computeNextRefresh(hwcLatency);
}
} // namespace impl
} // namespace android