1 /*
2  * Copyright 2022 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 #pragma once
18 
19 #include <memory>
20 #include <queue>
21 #include <utility>
22 
23 #include <scheduler/Time.h>
24 
25 namespace android {
26 
27 class FenceTime;
28 
29 namespace scheduler {
30 
31 // Computes composite-to-present latency by tracking recently composited frames pending to present.
32 class PresentLatencyTracker {
33 public:
34     // For tests.
35     static constexpr size_t kMaxPendingFrames = 4;
36 
37     // Returns the present latency of the latest frame.
38     Duration trackPendingFrame(TimePoint compositeTime,
39                                std::shared_ptr<FenceTime> presentFenceTime);
40 
41 private:
42     struct PendingFrame {
PendingFramePendingFrame43         PendingFrame(TimePoint compositeTime, std::shared_ptr<FenceTime> presentFenceTime)
44               : compositeTime(compositeTime), presentFenceTime(std::move(presentFenceTime)) {}
45 
46         const TimePoint compositeTime;
47         const std::shared_ptr<FenceTime> presentFenceTime;
48     };
49 
50     std::queue<PendingFrame> mPendingFrames;
51 };
52 
53 } // namespace scheduler
54 } // namespace android
55