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/*
* Copyright 2018 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.
*/
#pragma once
#include <chrono>
#include <mutex>
#include <optional>
#include <unordered_set>
#include <android-base/thread_annotations.h>
#include <binder/IBinder.h>
#include <utils/Timers.h>
namespace android::scheduler {
// State machine controlled by transaction flags. VsyncModulator switches to early phase offsets
// when a transaction is flagged EarlyStart or Early, lasting until an EarlyEnd transaction or a
// fixed number of frames, respectively.
enum class TransactionSchedule {
Late, // Default.
EarlyStart,
EarlyEnd
};
// Modulates VSYNC phase depending on transaction schedule and refresh rate changes.
class VsyncModulator : public IBinder::DeathRecipient {
public:
// Number of frames to keep early offsets after an early transaction or GPU composition.
// This acts as a low-pass filter in case subsequent transactions are delayed, or if the
// composition strategy alternates on subsequent frames.
static constexpr int MIN_EARLY_TRANSACTION_FRAMES = 2;
static constexpr int MIN_EARLY_GPU_FRAMES = 2;
// Duration to delay the MIN_EARLY_TRANSACTION_FRAMES countdown after an early transaction.
// This may keep early offsets for an extra frame, but avoids a race with transaction commit.
static const std::chrono::nanoseconds MIN_EARLY_TRANSACTION_TIME;
// Phase offsets and work durations for SF and app deadlines from VSYNC.
struct VsyncConfig {
nsecs_t sfOffset;
nsecs_t appOffset;
std::chrono::nanoseconds sfWorkDuration;
std::chrono::nanoseconds appWorkDuration;
bool operator==(const VsyncConfig& other) const {
return sfOffset == other.sfOffset && appOffset == other.appOffset &&
sfWorkDuration == other.sfWorkDuration &&
appWorkDuration == other.appWorkDuration;
}
bool operator!=(const VsyncConfig& other) const { return !(*this == other); }
};
using VsyncConfigOpt = std::optional<VsyncConfig>;
struct VsyncConfigSet {
VsyncConfig early; // Used for early transactions, and during refresh rate change.
VsyncConfig earlyGpu; // Used during GPU composition.
VsyncConfig late; // Default.
std::chrono::nanoseconds hwcMinWorkDuration; // Used for calculating the
// earliest present time
bool operator==(const VsyncConfigSet& other) const {
return early == other.early && earlyGpu == other.earlyGpu && late == other.late &&
hwcMinWorkDuration == other.hwcMinWorkDuration;
}
bool operator!=(const VsyncConfigSet& other) const { return !(*this == other); }
};
using Clock = std::chrono::steady_clock;
using TimePoint = Clock::time_point;
using Now = TimePoint (*)();
explicit VsyncModulator(const VsyncConfigSet&, Now = Clock::now);
VsyncConfig getVsyncConfig() const EXCLUDES(mMutex);
[[nodiscard]] VsyncConfig setVsyncConfigSet(const VsyncConfigSet&) EXCLUDES(mMutex);
// Changes offsets in response to transaction flags or commit.
[[nodiscard]] VsyncConfigOpt setTransactionSchedule(TransactionSchedule,
const sp<IBinder>& = {}) EXCLUDES(mMutex);
[[nodiscard]] VsyncConfigOpt onTransactionCommit();
// Called when we send a refresh rate change to hardware composer, so that
// we can move into early offsets.
[[nodiscard]] VsyncConfigOpt onRefreshRateChangeInitiated();
// Called when we detect from VSYNC signals that the refresh rate changed.
// This way we can move out of early offsets if no longer necessary.
[[nodiscard]] VsyncConfigOpt onRefreshRateChangeCompleted();
[[nodiscard]] VsyncConfigOpt onDisplayRefresh(bool usedGpuComposition);
protected:
// Called from unit tests as well
void binderDied(const wp<IBinder>&) override EXCLUDES(mMutex);
private:
const VsyncConfig& getNextVsyncConfig() const REQUIRES(mMutex);
[[nodiscard]] VsyncConfig updateVsyncConfig() EXCLUDES(mMutex);
[[nodiscard]] VsyncConfig updateVsyncConfigLocked() REQUIRES(mMutex);
mutable std::mutex mMutex;
VsyncConfigSet mVsyncConfigSet GUARDED_BY(mMutex);
VsyncConfig mVsyncConfig GUARDED_BY(mMutex){mVsyncConfigSet.late};
using Schedule = TransactionSchedule;
std::atomic<Schedule> mTransactionSchedule = Schedule::Late;
struct WpHash {
size_t operator()(const wp<IBinder>& p) const {
return std::hash<IBinder*>()(p.unsafe_get());
}
};
std::unordered_set<wp<IBinder>, WpHash> mEarlyWakeupRequests GUARDED_BY(mMutex);
std::atomic<bool> mRefreshRateChangePending = false;
std::atomic<int> mEarlyTransactionFrames = 0;
std::atomic<int> mEarlyGpuFrames = 0;
std::atomic<TimePoint> mEarlyTransactionStartTime = TimePoint();
std::atomic<TimePoint> mLastTransactionCommitTime = TimePoint();
const Now mNow;
const bool mTraceDetailedInfo;
};
} // namespace android::scheduler
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