1/*
2 * Copyright 2016 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
18#ifndef ANDROID_GUI_OCCUPANCYTRACKER_H
19#define ANDROID_GUI_OCCUPANCYTRACKER_H
20
21#include <binder/Parcelable.h>
22
23#include <utils/Timers.h>
24
25#include <deque>
26#include <unordered_map>
27
28namespace android {
29
30class String8;
31
32class OccupancyTracker
33{
34public:
35    OccupancyTracker()
36      : mPendingSegment(),
37        mSegmentHistory(),
38        mLastOccupancy(0),
39        mLastOccupancyChangeTime(0) {}
40
41    struct Segment : public Parcelable {
42        Segment()
43          : totalTime(0),
44            numFrames(0),
45            occupancyAverage(0.0f),
46            usedThirdBuffer(false) {}
47
48        Segment(nsecs_t _totalTime, size_t _numFrames, float _occupancyAverage,
49                bool _usedThirdBuffer)
50          : totalTime(_totalTime),
51            numFrames(_numFrames),
52            occupancyAverage(_occupancyAverage),
53            usedThirdBuffer(_usedThirdBuffer) {}
54
55        // Parcelable interface
56        virtual status_t writeToParcel(Parcel* parcel) const override;
57        virtual status_t readFromParcel(const Parcel* parcel) override;
58
59        nsecs_t totalTime;
60        size_t numFrames;
61
62        // Average occupancy of the queue over this segment. (0.0, 1.0) implies
63        // double-buffered, (1.0, 2.0) implies triple-buffered.
64        float occupancyAverage;
65
66        // Whether a third buffer was used at all during this segment (since a
67        // segment could read as double-buffered on average, but still require a
68        // third buffer to avoid jank for some smaller portion)
69        bool usedThirdBuffer;
70    };
71
72    void registerOccupancyChange(size_t occupancy);
73    std::vector<Segment> getSegmentHistory(bool forceFlush);
74
75private:
76    static constexpr size_t MAX_HISTORY_SIZE = 10;
77    static constexpr nsecs_t NEW_SEGMENT_DELAY = ms2ns(100);
78    static constexpr size_t LONG_SEGMENT_THRESHOLD = 3;
79
80    struct PendingSegment {
81        void clear() {
82            totalTime = 0;
83            numFrames = 0;
84            mOccupancyTimes.clear();
85        }
86
87        nsecs_t totalTime;
88        size_t numFrames;
89        std::unordered_map<size_t, nsecs_t> mOccupancyTimes;
90    };
91
92    void recordPendingSegment();
93
94    PendingSegment mPendingSegment;
95    std::deque<Segment> mSegmentHistory;
96
97    size_t mLastOccupancy;
98    nsecs_t mLastOccupancyChangeTime;
99
100}; // class OccupancyTracker
101
102} // namespace android
103
104#endif
105