2 * Copyright (C) 2012 The Android Open Source Project
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 #ifndef ANDROID_FRAMETRACKER_H
18 #define ANDROID_FRAMETRACKER_H
20 #include <ui/FenceTime.h>
24 #include <utils/Mutex.h>
25 #include <utils/Timers.h>
26 #include <utils/RefBase.h>
32 // FrameTracker tracks information about the most recently rendered frames. It
33 // uses a circular buffer of frame records, and is *NOT* thread-safe -
34 // mutexing must be done at a higher level if multi-threaded access is
37 // Some of the time values tracked may be set either as a specific timestamp
38 // or a fence. When a non-NULL fence is set for a given time value, the
39 // signal time of that fence is used instead of the timestamp.
43 // NUM_FRAME_RECORDS is the size of the circular buffer used to track the
44 // frame time history.
45 enum { NUM_FRAME_RECORDS = 128 };
47 enum { NUM_FRAME_BUCKETS = 7 };
51 // setDesiredPresentTime sets the time at which the current frame
52 // should be presented to the user under ideal (i.e. zero latency)
54 void setDesiredPresentTime(nsecs_t desiredPresentTime);
56 // setFrameReadyTime sets the time at which the current frame became ready
57 // to be presented to the user. For example, if the frame contents is
58 // being written to memory by some asynchronous hardware, this would be
59 // the time at which those writes completed.
60 void setFrameReadyTime(nsecs_t readyTime);
62 // setFrameReadyFence sets the fence that is used to get the time at which
63 // the current frame became ready to be presented to the user.
64 void setFrameReadyFence(std::shared_ptr<FenceTime>&& readyFence);
66 // setActualPresentTime sets the timestamp at which the current frame became
67 // visible to the user.
68 void setActualPresentTime(nsecs_t displayTime);
70 // setActualPresentFence sets the fence that is used to get the time
71 // at which the current frame became visible to the user.
72 void setActualPresentFence(std::shared_ptr<FenceTime>&& fence);
74 // setDisplayRefreshPeriod sets the display refresh period in nanoseconds.
75 // This is used to compute frame presentation duration statistics relative
77 void setDisplayRefreshPeriod(nsecs_t displayPeriod);
79 // advanceFrame advances the frame tracker to the next frame.
82 // clearStats clears the tracked frame stats.
85 // getStats gets the tracked frame stats.
86 void getStats(FrameStats* outStats) const;
88 // logAndResetStats dumps the current statistics to the binary event log
89 // and then resets the accumulated statistics to their initial values.
90 void logAndResetStats(const String8& name);
92 // dumpStats dump appends the current frame display time history to the result string.
93 void dumpStats(String8& result) const;
98 desiredPresentTime(0),
100 actualPresentTime(0) {}
101 nsecs_t desiredPresentTime;
102 nsecs_t frameReadyTime;
103 nsecs_t actualPresentTime;
104 std::shared_ptr<FenceTime> frameReadyFence;
105 std::shared_ptr<FenceTime> actualPresentFence;
108 // processFences iterates over all the frame records that have a fence set
109 // and replaces that fence with a timestamp if the fence has signaled. If
110 // the fence is not signaled the record's displayTime is set to INT64_MAX.
112 // This method is const because although it modifies the frame records it
113 // does so in such a way that the information represented should not
114 // change. This allows it to be called from the dump method.
115 void processFencesLocked() const;
117 // updateStatsLocked updates the running statistics that are gathered
118 // about the frame times.
119 void updateStatsLocked(size_t newFrameIdx) const;
121 // resetFrameCounteresLocked sets all elements of the mNumFrames array to
123 void resetFrameCountersLocked();
125 // logStatsLocked dumps the current statistics to the binary event log.
126 void logStatsLocked(const String8& name) const;
128 // isFrameValidLocked returns true if the data for the given frame index is
129 // valid and has all arrived (i.e. there are no oustanding fences).
130 bool isFrameValidLocked(size_t idx) const;
132 // mFrameRecords is the circular buffer storing the tracked data for each
134 FrameRecord mFrameRecords[NUM_FRAME_RECORDS];
136 // mOffset is the offset into mFrameRecords of the current frame.
139 // mNumFences is the total number of fences set in the frame records. It
140 // is incremented each time a fence is added and decremented each time a
141 // signaled fence is removed in processFences or if advanceFrame clobbers
144 // The number of fences is tracked so that the run time of processFences
145 // doesn't grow with NUM_FRAME_RECORDS.
148 // mNumFrames keeps a count of the number of frames with a duration in a
149 // particular range of vsync periods. Element n of the array stores the
150 // number of frames with duration in the half-inclusive range
151 // [2^n, 2^(n+1)). The last element of the array contains the count for
152 // all frames with duration greater than 2^(NUM_FRAME_BUCKETS-1).
153 int32_t mNumFrames[NUM_FRAME_BUCKETS];
155 // mDisplayPeriod is the display refresh period of the display for which
156 // this FrameTracker is gathering information.
157 nsecs_t mDisplayPeriod;
159 // mMutex is used to protect access to all member variables.
160 mutable Mutex mMutex;
165 #endif // ANDROID_FRAMETRACKER_H