1 /* 2 * Copyright (C) 2012 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 #ifndef ANDROID_FRAMETRACKER_H 18 #define ANDROID_FRAMETRACKER_H 19 20 #include <stddef.h> 21 22 #include <utils/Mutex.h> 23 #include <utils/Timers.h> 24 #include <utils/RefBase.h> 25 26 namespace android { 27 28 class String8; 29 class Fence; 30 31 // FrameTracker tracks information about the most recently rendered frames. It 32 // uses a circular buffer of frame records, and is *NOT* thread-safe - 33 // mutexing must be done at a higher level if multi-threaded access is 34 // possible. 35 // 36 // Some of the time values tracked may be set either as a specific timestamp 37 // or a fence. When a non-NULL fence is set for a given time value, the 38 // signal time of that fence is used instead of the timestamp. 39 class FrameTracker { 40 41 public: 42 // NUM_FRAME_RECORDS is the size of the circular buffer used to track the 43 // frame time history. 44 enum { NUM_FRAME_RECORDS = 128 }; 45 46 enum { NUM_FRAME_BUCKETS = 7 }; 47 48 FrameTracker(); 49 50 // setDesiredPresentTime sets the time at which the current frame 51 // should be presented to the user under ideal (i.e. zero latency) 52 // conditions. 53 void setDesiredPresentTime(nsecs_t desiredPresentTime); 54 55 // setFrameReadyTime sets the time at which the current frame became ready 56 // to be presented to the user. For example, if the frame contents is 57 // being written to memory by some asynchronous hardware, this would be 58 // the time at which those writes completed. 59 void setFrameReadyTime(nsecs_t readyTime); 60 61 // setFrameReadyFence sets the fence that is used to get the time at which 62 // the current frame became ready to be presented to the user. 63 void setFrameReadyFence(const sp<Fence>& readyFence); 64 65 // setActualPresentTime sets the timestamp at which the current frame became 66 // visible to the user. 67 void setActualPresentTime(nsecs_t displayTime); 68 69 // setActualPresentFence sets the fence that is used to get the time 70 // at which the current frame became visible to the user. 71 void setActualPresentFence(const sp<Fence>& fence); 72 73 // setDisplayRefreshPeriod sets the display refresh period in nanoseconds. 74 // This is used to compute frame presentation duration statistics relative 75 // to this period. 76 void setDisplayRefreshPeriod(nsecs_t displayPeriod); 77 78 // advanceFrame advances the frame tracker to the next frame. 79 void advanceFrame(); 80 81 // clearStats clears the tracked frame stats. 82 void clearStats(); 83 84 // getStats gets the tracked frame stats. 85 void getStats(FrameStats* outStats) const; 86 87 // logAndResetStats dumps the current statistics to the binary event log 88 // and then resets the accumulated statistics to their initial values. 89 void logAndResetStats(const String8& name); 90 91 // dumpStats dump appends the current frame display time history to the result string. 92 void dumpStats(String8& result) const; 93 94 private: 95 struct FrameRecord { 96 FrameRecord() : 97 desiredPresentTime(0), 98 frameReadyTime(0), 99 actualPresentTime(0) {} 100 nsecs_t desiredPresentTime; 101 nsecs_t frameReadyTime; 102 nsecs_t actualPresentTime; 103 sp<Fence> frameReadyFence; 104 sp<Fence> actualPresentFence; 105 }; 106 107 // processFences iterates over all the frame records that have a fence set 108 // and replaces that fence with a timestamp if the fence has signaled. If 109 // the fence is not signaled the record's displayTime is set to INT64_MAX. 110 // 111 // This method is const because although it modifies the frame records it 112 // does so in such a way that the information represented should not 113 // change. This allows it to be called from the dump method. 114 void processFencesLocked() const; 115 116 // updateStatsLocked updates the running statistics that are gathered 117 // about the frame times. 118 void updateStatsLocked(size_t newFrameIdx) const; 119 120 // resetFrameCounteresLocked sets all elements of the mNumFrames array to 121 // 0. 122 void resetFrameCountersLocked(); 123 124 // logStatsLocked dumps the current statistics to the binary event log. 125 void logStatsLocked(const String8& name) const; 126 127 // isFrameValidLocked returns true if the data for the given frame index is 128 // valid and has all arrived (i.e. there are no oustanding fences). 129 bool isFrameValidLocked(size_t idx) const; 130 131 // mFrameRecords is the circular buffer storing the tracked data for each 132 // frame. 133 FrameRecord mFrameRecords[NUM_FRAME_RECORDS]; 134 135 // mOffset is the offset into mFrameRecords of the current frame. 136 size_t mOffset; 137 138 // mNumFences is the total number of fences set in the frame records. It 139 // is incremented each time a fence is added and decremented each time a 140 // signaled fence is removed in processFences or if advanceFrame clobbers 141 // a fence. 142 // 143 // The number of fences is tracked so that the run time of processFences 144 // doesn't grow with NUM_FRAME_RECORDS. 145 int mNumFences; 146 147 // mNumFrames keeps a count of the number of frames with a duration in a 148 // particular range of vsync periods. Element n of the array stores the 149 // number of frames with duration in the half-inclusive range 150 // [2^n, 2^(n+1)). The last element of the array contains the count for 151 // all frames with duration greater than 2^(NUM_FRAME_BUCKETS-1). 152 int32_t mNumFrames[NUM_FRAME_BUCKETS]; 153 154 // mDisplayPeriod is the display refresh period of the display for which 155 // this FrameTracker is gathering information. 156 nsecs_t mDisplayPeriod; 157 158 // mMutex is used to protect access to all member variables. 159 mutable Mutex mMutex; 160 }; 161 162 } 163 164 #endif // ANDROID_FRAMETRACKER_H 165
