services/surfaceflinger/Scheduler/VsyncModulator.cpp

/*
 * Copyright 2019 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

#undef LOG_TAG
#define LOG_TAG "VsyncModulator"

#include "VsyncModulator.h"

#include <android-base/properties.h>
#include <log/log.h>
#include <utils/Trace.h>

#include <chrono>
#include <cinttypes>
#include <mutex>

using namespace std::chrono_literals;

namespace android::scheduler {

const std::chrono::nanoseconds VsyncModulator::MIN_EARLY_TRANSACTION_TIME = 1ms;

VsyncModulator::VsyncModulator(const VsyncConfigSet& config, Now now)
      : mVsyncConfigSet(config),
        mNow(now),
        mTraceDetailedInfo(base::GetBoolProperty("debug.sf.vsync_trace_detailed_info", false)) {}

VsyncModulator::VsyncConfig VsyncModulator::setVsyncConfigSet(const VsyncConfigSet& config) {
    std::lock_guard<std::mutex> lock(mMutex);
    mVsyncConfigSet = config;
    return updateVsyncConfigLocked();
}

VsyncModulator::VsyncConfigOpt VsyncModulator::setTransactionSchedule(
        TransactionSchedule schedule) {
    switch (schedule) {
        case Schedule::EarlyStart:
            ALOGW_IF(mEarlyWakeup, "%s: Duplicate EarlyStart", __FUNCTION__);
            mEarlyWakeup = true;
            break;
        case Schedule::EarlyEnd:
            ALOGW_IF(!mEarlyWakeup, "%s: Unexpected EarlyEnd", __FUNCTION__);
            mEarlyWakeup = false;
            break;
        case Schedule::Late:
            // No change to mEarlyWakeup for non-explicit states.
            break;
    }

    if (mTraceDetailedInfo) {
        ATRACE_INT("mEarlyWakeup", mEarlyWakeup);
    }

    if (!mEarlyWakeup && schedule == Schedule::EarlyEnd) {
        mEarlyTransactionFrames = MIN_EARLY_TRANSACTION_FRAMES;
        mEarlyTransactionStartTime = mNow();
    }

    // An early transaction stays an early transaction.
    if (schedule == mTransactionSchedule || mTransactionSchedule == Schedule::EarlyEnd) {
        return std::nullopt;
    }
    mTransactionSchedule = schedule;
    return updateVsyncConfig();
}

VsyncModulator::VsyncConfigOpt VsyncModulator::onTransactionCommit() {
    mLastTransactionCommitTime = mNow();
    if (mTransactionSchedule == Schedule::Late) return std::nullopt;
    mTransactionSchedule = Schedule::Late;
    return updateVsyncConfig();
}

VsyncModulator::VsyncConfigOpt VsyncModulator::onRefreshRateChangeInitiated() {
    if (mRefreshRateChangePending) return std::nullopt;
    mRefreshRateChangePending = true;
    return updateVsyncConfig();
}

VsyncModulator::VsyncConfigOpt VsyncModulator::onRefreshRateChangeCompleted() {
    if (!mRefreshRateChangePending) return std::nullopt;
    mRefreshRateChangePending = false;
    return updateVsyncConfig();
}

VsyncModulator::VsyncConfigOpt VsyncModulator::onDisplayRefresh(bool usedGpuComposition) {
    bool updateOffsetsNeeded = false;

    if (mEarlyTransactionStartTime.load() + MIN_EARLY_TRANSACTION_TIME <=
        mLastTransactionCommitTime.load()) {
        if (mEarlyTransactionFrames > 0) {
            mEarlyTransactionFrames--;
            updateOffsetsNeeded = true;
        }
    }
    if (usedGpuComposition) {
        mEarlyGpuFrames = MIN_EARLY_GPU_FRAMES;
        updateOffsetsNeeded = true;
    } else if (mEarlyGpuFrames > 0) {
        mEarlyGpuFrames--;
        updateOffsetsNeeded = true;
    }

    if (!updateOffsetsNeeded) return std::nullopt;
    return updateVsyncConfig();
}

VsyncModulator::VsyncConfig VsyncModulator::getVsyncConfig() const {
    std::lock_guard<std::mutex> lock(mMutex);
    return mVsyncConfig;
}

const VsyncModulator::VsyncConfig& VsyncModulator::getNextVsyncConfig() const {
    // Early offsets are used if we're in the middle of a refresh rate
    // change, or if we recently begin a transaction.
    if (mEarlyWakeup || mTransactionSchedule == Schedule::EarlyEnd || mEarlyTransactionFrames > 0 ||
        mRefreshRateChangePending) {
        return mVsyncConfigSet.early;
    } else if (mEarlyGpuFrames > 0) {
        return mVsyncConfigSet.earlyGpu;
    } else {
        return mVsyncConfigSet.late;
    }
}

VsyncModulator::VsyncConfig VsyncModulator::updateVsyncConfig() {
    std::lock_guard<std::mutex> lock(mMutex);
    return updateVsyncConfigLocked();
}

VsyncModulator::VsyncConfig VsyncModulator::updateVsyncConfigLocked() {
    const VsyncConfig& offsets = getNextVsyncConfig();
    mVsyncConfig = offsets;

    if (mTraceDetailedInfo) {
        const bool isEarly = &offsets == &mVsyncConfigSet.early;
        const bool isEarlyGpu = &offsets == &mVsyncConfigSet.earlyGpu;
        const bool isLate = &offsets == &mVsyncConfigSet.late;

        ATRACE_INT("Vsync-EarlyOffsetsOn", isEarly);
        ATRACE_INT("Vsync-EarlyGpuOffsetsOn", isEarlyGpu);
        ATRACE_INT("Vsync-LateOffsetsOn", isLate);
    }

    return offsets;
}

} // namespace android::scheduler