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/*
* 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.
*/
#pragma once
#include <android-base/thread_annotations.h>
#include <mutex>
#include <unordered_map>
#include <vector>
#include "SchedulerUtils.h"
#include "VSyncTracker.h"
namespace android::scheduler {
class VSyncPredictor : public VSyncTracker {
public:
/*
* \param [in] idealPeriod The initial ideal period to use.
* \param [in] historySize The internal amount of entries to store in the model.
* \param [in] minimumSamplesForPrediction The minimum number of samples to collect before
* predicting. \param [in] outlierTolerancePercent a number 0 to 100 that will be used to filter
* samples that fall outlierTolerancePercent from an anticipated vsync event.
*/
VSyncPredictor(nsecs_t idealPeriod, size_t historySize, size_t minimumSamplesForPrediction,
uint32_t outlierTolerancePercent);
~VSyncPredictor();
bool addVsyncTimestamp(nsecs_t timestamp) final EXCLUDES(mMutex);
nsecs_t nextAnticipatedVSyncTimeFrom(nsecs_t timePoint) const final EXCLUDES(mMutex);
nsecs_t currentPeriod() const final EXCLUDES(mMutex);
void resetModel() final EXCLUDES(mMutex);
/*
* Inform the model that the period is anticipated to change to a new value.
* model will use the period parameter to predict vsync events until enough
* timestamps with the new period have been collected.
*
* \param [in] period The new period that should be used.
*/
void setPeriod(nsecs_t period) final EXCLUDES(mMutex);
/* Query if the model is in need of more samples to make a prediction.
* \return True, if model would benefit from more samples, False if not.
*/
bool needsMoreSamples() const final EXCLUDES(mMutex);
struct Model {
nsecs_t slope;
nsecs_t intercept;
};
VSyncPredictor::Model getVSyncPredictionModel() const EXCLUDES(mMutex);
bool isVSyncInPhase(nsecs_t timePoint, Fps frameRate) const final EXCLUDES(mMutex);
void dump(std::string& result) const final EXCLUDES(mMutex);
private:
VSyncPredictor(VSyncPredictor const&) = delete;
VSyncPredictor& operator=(VSyncPredictor const&) = delete;
void clearTimestamps() REQUIRES(mMutex);
inline void traceInt64If(const char* name, int64_t value) const;
bool const mTraceOn;
size_t const kHistorySize;
size_t const kMinimumSamplesForPrediction;
size_t const kOutlierTolerancePercent;
std::mutex mutable mMutex;
size_t next(size_t i) const REQUIRES(mMutex);
bool validate(nsecs_t timestamp) const REQUIRES(mMutex);
Model getVSyncPredictionModelLocked() const REQUIRES(mMutex);
nsecs_t nextAnticipatedVSyncTimeFromLocked(nsecs_t timePoint) const REQUIRES(mMutex);
nsecs_t mIdealPeriod GUARDED_BY(mMutex);
std::optional<nsecs_t> mKnownTimestamp GUARDED_BY(mMutex);
// Map between ideal vsync period and the calculated model
std::unordered_map<nsecs_t, Model> mutable mRateMap GUARDED_BY(mMutex);
// Map between the divided vsync period and the last known vsync timestamp
std::unordered_map<nsecs_t, nsecs_t> mutable mRateDividerKnownTimestampMap GUARDED_BY(mMutex);
size_t mLastTimestampIndex GUARDED_BY(mMutex) = 0;
std::vector<nsecs_t> mTimestamps GUARDED_BY(mMutex);
};
} // namespace android::scheduler
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