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 #include <ui/DisplayId.h> 25 26 #include "VSyncTracker.h" 27 28 namespace android::scheduler { 29 30 class VSyncPredictor : public VSyncTracker { 31 public: 32 /* 33 * \param [in] PhysicalDisplayid The display this corresponds to. 34 * \param [in] idealPeriod The initial ideal period to use. 35 * \param [in] historySize The internal amount of entries to store in the model. 36 * \param [in] minimumSamplesForPrediction The minimum number of samples to collect before 37 * predicting. \param [in] outlierTolerancePercent a number 0 to 100 that will be used to filter 38 * samples that fall outlierTolerancePercent from an anticipated vsync event. 39 */ 40 VSyncPredictor(PhysicalDisplayId, nsecs_t idealPeriod, size_t historySize, 41 size_t minimumSamplesForPrediction, uint32_t outlierTolerancePercent); 42 ~VSyncPredictor(); 43 44 bool addVsyncTimestamp(nsecs_t timestamp) final EXCLUDES(mMutex); 45 nsecs_t nextAnticipatedVSyncTimeFrom(nsecs_t timePoint) const final EXCLUDES(mMutex); 46 nsecs_t currentPeriod() const final EXCLUDES(mMutex); 47 void resetModel() final EXCLUDES(mMutex); 48 49 /* 50 * Inform the model that the period is anticipated to change to a new value. 51 * model will use the period parameter to predict vsync events until enough 52 * timestamps with the new period have been collected. 53 * 54 * \param [in] period The new period that should be used. 55 */ 56 void setPeriod(nsecs_t period) final EXCLUDES(mMutex); 57 58 /* Query if the model is in need of more samples to make a prediction. 59 * \return True, if model would benefit from more samples, False if not. 60 */ 61 bool needsMoreSamples() const final EXCLUDES(mMutex); 62 63 struct Model { 64 nsecs_t slope; 65 nsecs_t intercept; 66 }; 67 68 VSyncPredictor::Model getVSyncPredictionModel() const EXCLUDES(mMutex); 69 70 bool isVSyncInPhase(nsecs_t timePoint, Fps frameRate) const final EXCLUDES(mMutex); 71 72 void setRenderRate(Fps) final EXCLUDES(mMutex); 73 74 void dump(std::string& result) const final EXCLUDES(mMutex); 75 76 private: 77 VSyncPredictor(VSyncPredictor const&) = delete; 78 VSyncPredictor& operator=(VSyncPredictor const&) = delete; 79 void clearTimestamps() REQUIRES(mMutex); 80 81 const PhysicalDisplayId mId; 82 83 inline void traceInt64If(const char* name, int64_t value) const; 84 inline void traceInt64(const char* name, int64_t value) const; 85 86 size_t next(size_t i) const REQUIRES(mMutex); 87 bool validate(nsecs_t timestamp) const REQUIRES(mMutex); 88 Model getVSyncPredictionModelLocked() const REQUIRES(mMutex); 89 nsecs_t nextAnticipatedVSyncTimeFromLocked(nsecs_t timePoint) const REQUIRES(mMutex); 90 bool isVSyncInPhaseLocked(nsecs_t timePoint, unsigned divisor) const REQUIRES(mMutex); 91 92 struct VsyncSequence { 93 nsecs_t vsyncTime; 94 int64_t seq; 95 }; 96 VsyncSequence getVsyncSequenceLocked(nsecs_t timestamp) const REQUIRES(mMutex); 97 98 bool const mTraceOn; 99 size_t const kHistorySize; 100 size_t const kMinimumSamplesForPrediction; 101 size_t const kOutlierTolerancePercent; 102 std::mutex mutable mMutex; 103 104 nsecs_t mIdealPeriod GUARDED_BY(mMutex); 105 std::optional<nsecs_t> mKnownTimestamp GUARDED_BY(mMutex); 106 107 // Map between ideal vsync period and the calculated model 108 std::unordered_map<nsecs_t, Model> mutable mRateMap GUARDED_BY(mMutex); 109 110 size_t mLastTimestampIndex GUARDED_BY(mMutex) = 0; 111 std::vector<nsecs_t> mTimestamps GUARDED_BY(mMutex); 112 113 std::optional<Fps> mRenderRate GUARDED_BY(mMutex); 114 115 mutable std::optional<VsyncSequence> mLastVsyncSequence GUARDED_BY(mMutex); 116 }; 117 118 } // namespace android::scheduler 119