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 #undef LOG_TAG
18 #define LOG_TAG "OccupancyTracker"
19 
20 #include <gui/OccupancyTracker.h>
21 #include <binder/Parcel.h>
22 #include <utils/String8.h>
23 #include <utils/Trace.h>
24 
25 #include <inttypes.h>
26 
27 namespace android {
28 
writeToParcel(Parcel * parcel) const29 status_t OccupancyTracker::Segment::writeToParcel(Parcel* parcel) const {
30     status_t result = parcel->writeInt64(totalTime);
31     if (result != OK) {
32         return result;
33     }
34     result = parcel->writeUint64(static_cast<uint64_t>(numFrames));
35     if (result != OK) {
36         return result;
37     }
38     result = parcel->writeFloat(occupancyAverage);
39     if (result != OK) {
40         return result;
41     }
42     return parcel->writeBool(usedThirdBuffer);
43 }
44 
readFromParcel(const Parcel * parcel)45 status_t OccupancyTracker::Segment::readFromParcel(const Parcel* parcel) {
46     status_t result = parcel->readInt64(&totalTime);
47     if (result != OK) {
48         return result;
49     }
50     uint64_t uintNumFrames = 0;
51     result = parcel->readUint64(&uintNumFrames);
52     if (result != OK) {
53         return result;
54     }
55     numFrames = static_cast<size_t>(uintNumFrames);
56     result = parcel->readFloat(&occupancyAverage);
57     if (result != OK) {
58         return result;
59     }
60     return parcel->readBool(&usedThirdBuffer);
61 }
62 
registerOccupancyChange(size_t occupancy)63 void OccupancyTracker::registerOccupancyChange(size_t occupancy) {
64     ATRACE_CALL();
65     nsecs_t now = systemTime();
66     nsecs_t delta = now - mLastOccupancyChangeTime;
67     if (delta > NEW_SEGMENT_DELAY) {
68         recordPendingSegment();
69     } else {
70         mPendingSegment.totalTime += delta;
71         if (mPendingSegment.mOccupancyTimes.count(mLastOccupancy)) {
72             mPendingSegment.mOccupancyTimes[mLastOccupancy] += delta;
73         } else {
74             mPendingSegment.mOccupancyTimes[mLastOccupancy] = delta;
75         }
76     }
77     if (occupancy > mLastOccupancy) {
78         ++mPendingSegment.numFrames;
79     }
80     mLastOccupancyChangeTime = now;
81     mLastOccupancy = occupancy;
82 }
83 
getSegmentHistory(bool forceFlush)84 std::vector<OccupancyTracker::Segment> OccupancyTracker::getSegmentHistory(
85         bool forceFlush) {
86     if (forceFlush) {
87         recordPendingSegment();
88     }
89     std::vector<Segment> segments(mSegmentHistory.cbegin(),
90             mSegmentHistory.cend());
91     mSegmentHistory.clear();
92     return segments;
93 }
94 
recordPendingSegment()95 void OccupancyTracker::recordPendingSegment() {
96     // Only record longer segments to get a better measurement of actual double-
97     // vs. triple-buffered time
98     if (mPendingSegment.numFrames > LONG_SEGMENT_THRESHOLD) {
99         float occupancyAverage = 0.0f;
100         bool usedThirdBuffer = false;
101         for (const auto& timePair : mPendingSegment.mOccupancyTimes) {
102             size_t occupancy = timePair.first;
103             float timeRatio = static_cast<float>(timePair.second) /
104                     mPendingSegment.totalTime;
105             occupancyAverage += timeRatio * occupancy;
106             usedThirdBuffer = usedThirdBuffer || (occupancy > 1);
107         }
108         mSegmentHistory.push_front({mPendingSegment.totalTime,
109                 mPendingSegment.numFrames, occupancyAverage, usedThirdBuffer});
110         if (mSegmentHistory.size() > MAX_HISTORY_SIZE) {
111             mSegmentHistory.pop_back();
112         }
113     }
114     mPendingSegment.clear();
115 }
116 
117 } // namespace android
118