a733f89c05
Bug: 18226391 The issue occurs as a result of a dispatchFrame itself taking longer than 12ms, the alloted budget. The result is that a vsync request (which occured at the end) would miss the vsync that occured 1ms prior to the end of the frame. As a result it would end up waiting for the following vsync, essentially dropping to 30fps even though 60 could have been sustained. Fix this with a few tweaks. First, adjust the UI thread's delay bias from (now + 4ms) to (vsync + 4ms), this prevents RT animators from slowly drifting if the vsync occurs mid-task. Second, request a vsync preemptively prior to running callbacks. This way if any callbacks needs the next vsync and it takes "too long", we will catch that vsync. Finally, fix an issue where the display event queue was always drained & rejected at the end of a task loop. Instead, drain and reject all stale vsyncs. This still prevents the issue of both UI thread & RT thread trying to drive 2 frames in a single pulse, but also allows RT to notice that it missed a vsync pulse it needed and that it should speed-up a bit in response Change-Id: I9d6be037737e9283297898cac2e3563453e797cd
51 lines
1.4 KiB
C++
51 lines
1.4 KiB
C++
/*
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* Copyright (C) 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef TIMELORD_H
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#define TIMELORD_H
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#include <utils/Timers.h>
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namespace android {
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namespace uirenderer {
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namespace renderthread {
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class RenderThread;
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// This class serves as a helper to filter & manage frame times from multiple sources
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// ensuring that time flows linearly and smoothly
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class TimeLord {
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public:
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void setFrameInterval(nsecs_t intervalNanos) { mFrameIntervalNanos = intervalNanos; }
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// returns true if the vsync is newer, false if it was rejected for staleness
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bool vsyncReceived(nsecs_t vsync);
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nsecs_t computeFrameTimeMs();
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private:
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friend class RenderThread;
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TimeLord();
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~TimeLord() {}
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nsecs_t mFrameIntervalNanos;
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nsecs_t mFrameTimeNanos;
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};
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} /* namespace renderthread */
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} /* namespace uirenderer */
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} /* namespace android */
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#endif /* TIMELORD_H */
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