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/*
* Copyright (C) 2020 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "FrameRateMonitor.h"
namespace WebCore {
static constexpr Seconds MinimumAverageDuration = 1_s;
static constexpr Seconds MaxQueueDuration = 2_s;
static constexpr unsigned MaxFrameDelayCount = 3;
void FrameRateMonitor::update()
{
++m_frameCount;
auto frameTime = MonotonicTime::now().secondsSinceEpoch().value();
auto lastFrameTime = m_observedFrameTimeStamps.isEmpty() ? frameTime : m_observedFrameTimeStamps.last();
if (m_observedFrameRate) {
auto maxDelay = MaxFrameDelayCount / m_observedFrameRate;
if ((frameTime - lastFrameTime) > maxDelay)
m_lateFrameCallback({ MonotonicTime::fromRawSeconds(frameTime), MonotonicTime::fromRawSeconds(lastFrameTime), m_observedFrameRate, m_frameCount });
}
m_observedFrameTimeStamps.append(frameTime);
m_observedFrameTimeStamps.removeAllMatching([&](auto time) {
return time <= frameTime - MaxQueueDuration.value();
});
auto queueDuration = m_observedFrameTimeStamps.last() - m_observedFrameTimeStamps.first();
if (queueDuration > MinimumAverageDuration.value())
m_observedFrameRate = (m_observedFrameTimeStamps.size() / queueDuration);
}
}
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