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