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
22 #include <utils/Mutex.h>
23 #include <utils/Timers.h>
24 #include <utils/RefBase.h>
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
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.
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 };
46 enum { NUM_FRAME_BUCKETS = 7 };
50 // setDesiredPresentTime sets the time at which the current frame
51 // should be presented to the user under ideal (i.e. zero latency)
53 void setDesiredPresentTime(nsecs_t desiredPresentTime);
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);
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);
65 // setActualPresentTime sets the timestamp at which the current frame became
66 // visible to the user.
67 void setActualPresentTime(nsecs_t displayTime);
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);
73 // setDisplayRefreshPeriod sets the display refresh period in nanoseconds.
74 // This is used to compute frame presentation duration statistics relative
76 void setDisplayRefreshPeriod(nsecs_t displayPeriod);
78 // advanceFrame advances the frame tracker to the next frame.
81 // clear resets all the tracked frame data to zero.
84 // logAndResetStats dumps the current statistics to the binary event log
85 // and then resets the accumulated statistics to their initial values.
86 void logAndResetStats(const String8& name);
88 // dump appends the current frame display time history to the result string.
89 void dump(String8& result) const;
94 desiredPresentTime(0),
96 actualPresentTime(0) {}
97 nsecs_t desiredPresentTime;
98 nsecs_t frameReadyTime;
99 nsecs_t actualPresentTime;
100 sp<Fence> frameReadyFence;
101 sp<Fence> actualPresentFence;
104 // processFences iterates over all the frame records that have a fence set
105 // and replaces that fence with a timestamp if the fence has signaled. If
106 // the fence is not signaled the record's displayTime is set to INT64_MAX.
108 // This method is const because although it modifies the frame records it
109 // does so in such a way that the information represented should not
110 // change. This allows it to be called from the dump method.
111 void processFencesLocked() const;
113 // updateStatsLocked updates the running statistics that are gathered
114 // about the frame times.
115 void updateStatsLocked(size_t newFrameIdx) const;
117 // resetFrameCounteresLocked sets all elements of the mNumFrames array to
119 void resetFrameCountersLocked();
121 // logStatsLocked dumps the current statistics to the binary event log.
122 void logStatsLocked(const String8& name) const;
124 // isFrameValidLocked returns true if the data for the given frame index is
125 // valid and has all arrived (i.e. there are no oustanding fences).
126 bool isFrameValidLocked(size_t idx) const;
128 // mFrameRecords is the circular buffer storing the tracked data for each
130 FrameRecord mFrameRecords[NUM_FRAME_RECORDS];
132 // mOffset is the offset into mFrameRecords of the current frame.
135 // mNumFences is the total number of fences set in the frame records. It
136 // is incremented each time a fence is added and decremented each time a
137 // signaled fence is removed in processFences or if advanceFrame clobbers
140 // The number of fences is tracked so that the run time of processFences
141 // doesn't grow with NUM_FRAME_RECORDS.
144 // mNumFrames keeps a count of the number of frames with a duration in a
145 // particular range of vsync periods. Element n of the array stores the
146 // number of frames with duration in the half-inclusive range
147 // [2^n, 2^(n+1)). The last element of the array contains the count for
148 // all frames with duration greater than 2^(NUM_FRAME_BUCKETS-1).
149 int32_t mNumFrames[NUM_FRAME_BUCKETS];
151 // mDisplayPeriod is the display refresh period of the display for which
152 // this FrameTracker is gathering information.
153 nsecs_t mDisplayPeriod;
155 // mMutex is used to protect access to all member variables.
156 mutable Mutex mMutex;
161 #endif // ANDROID_FRAMETRACKER_H