1 /* 2 * Copyright 2019 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 #pragma once 18 19 #include <mutex> 20 #include <unordered_map> 21 #include <vector> 22 23 #include <android-base/thread_annotations.h> 24 25 #include "VSyncTracker.h" 26 27 namespace android::scheduler { 28 29 class VSyncPredictor : public VSyncTracker { 30 public: 31 /* 32 * \param [in] idealPeriod The initial ideal period to use. 33 * \param [in] historySize The internal amount of entries to store in the model. 34 * \param [in] minimumSamplesForPrediction The minimum number of samples to collect before 35 * predicting. \param [in] outlierTolerancePercent a number 0 to 100 that will be used to filter 36 * samples that fall outlierTolerancePercent from an anticipated vsync event. 37 */ 38 VSyncPredictor(nsecs_t idealPeriod, size_t historySize, size_t minimumSamplesForPrediction, 39 uint32_t outlierTolerancePercent); 40 ~VSyncPredictor(); 41 42 bool addVsyncTimestamp(nsecs_t timestamp) final EXCLUDES(mMutex); 43 nsecs_t nextAnticipatedVSyncTimeFrom(nsecs_t timePoint) const final EXCLUDES(mMutex); 44 nsecs_t currentPeriod() const final EXCLUDES(mMutex); 45 void resetModel() final EXCLUDES(mMutex); 46 47 /* 48 * Inform the model that the period is anticipated to change to a new value. 49 * model will use the period parameter to predict vsync events until enough 50 * timestamps with the new period have been collected. 51 * 52 * \param [in] period The new period that should be used. 53 */ 54 void setPeriod(nsecs_t period) final EXCLUDES(mMutex); 55 56 /* Query if the model is in need of more samples to make a prediction. 57 * \return True, if model would benefit from more samples, False if not. 58 */ 59 bool needsMoreSamples() const final EXCLUDES(mMutex); 60 61 struct Model { 62 nsecs_t slope; 63 nsecs_t intercept; 64 }; 65 66 VSyncPredictor::Model getVSyncPredictionModel() const EXCLUDES(mMutex); 67 68 bool isVSyncInPhase(nsecs_t timePoint, Fps frameRate) const final EXCLUDES(mMutex); 69 70 void dump(std::string& result) const final EXCLUDES(mMutex); 71 72 private: 73 VSyncPredictor(VSyncPredictor const&) = delete; 74 VSyncPredictor& operator=(VSyncPredictor const&) = delete; 75 void clearTimestamps() REQUIRES(mMutex); 76 77 inline void traceInt64If(const char* name, int64_t value) const; 78 bool const mTraceOn; 79 80 size_t const kHistorySize; 81 size_t const kMinimumSamplesForPrediction; 82 size_t const kOutlierTolerancePercent; 83 84 std::mutex mutable mMutex; 85 size_t next(size_t i) const REQUIRES(mMutex); 86 bool validate(nsecs_t timestamp) const REQUIRES(mMutex); 87 88 Model getVSyncPredictionModelLocked() const REQUIRES(mMutex); 89 90 nsecs_t nextAnticipatedVSyncTimeFromLocked(nsecs_t timePoint) const REQUIRES(mMutex); 91 92 nsecs_t mIdealPeriod GUARDED_BY(mMutex); 93 std::optional<nsecs_t> mKnownTimestamp GUARDED_BY(mMutex); 94 95 // Map between ideal vsync period and the calculated model 96 std::unordered_map<nsecs_t, Model> mutable mRateMap GUARDED_BY(mMutex); 97 98 // Map between the divided vsync period and the last known vsync timestamp 99 std::unordered_map<nsecs_t, nsecs_t> mutable mRateDivisorKnownTimestampMap GUARDED_BY(mMutex); 100 101 size_t mLastTimestampIndex GUARDED_BY(mMutex) = 0; 102 std::vector<nsecs_t> mTimestamps GUARDED_BY(mMutex); 103 }; 104 105 } // namespace android::scheduler 106