[cc] Rename all cc/ filenames to Chromium style

BUG=155413

Review URL: https://codereview.chromium.org/11122003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@161671 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 132 insertions, 0 deletions

diff --git a/cc/frame_rate_counter.cc b/cc/frame_rate_counter.cc
new file mode 100644
index 0000000..80074ed
--- /dev/null
+++ b/cc/frame_rate_counter.cc
@@ -0,0 +1,132 @@
+// Copyright 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+
+#if USE(ACCELERATED_COMPOSITING)
+#include "CCFrameRateCounter.h"
+
+#include <cmath>
+
+#include "CCProxy.h"
+#include <public/Platform.h>
+#include <wtf/CurrentTime.h>
+
+namespace cc {
+
+const double CCFrameRateCounter::kFrameTooFast = 1.0 / 70.0; // measured in seconds
+const double CCFrameRateCounter::kFrameTooSlow = 1.0 / 12.0;
+const double CCFrameRateCounter::kDroppedFrameTime = 1.0 / 50.0;
+
+// safeMod works on -1, returning m-1 in that case.
+static inline int safeMod(int number, int modulus)
+{
+    return (number + modulus) % modulus;
+}
+
+inline double CCFrameRateCounter::frameInterval(int frameNumber) const
+{
+    return m_timeStampHistory[frameIndex(frameNumber)] -
+        m_timeStampHistory[frameIndex(frameNumber - 1)];
+}
+
+inline int CCFrameRateCounter::frameIndex(int frameNumber) const
+{
+    return safeMod(frameNumber, kTimeStampHistorySize);
+}
+
+CCFrameRateCounter::CCFrameRateCounter()
+    : m_currentFrameNumber(1)
+    , m_droppedFrameCount(0)
+{
+    m_timeStampHistory[0] = currentTime();
+    m_timeStampHistory[1] = m_timeStampHistory[0];
+    for (int i = 2; i < kTimeStampHistorySize; i++)
+        m_timeStampHistory[i] = 0;
+}
+
+void CCFrameRateCounter::markBeginningOfFrame(double timestamp)
+{
+    m_timeStampHistory[frameIndex(m_currentFrameNumber)] = timestamp;
+    double frameIntervalSeconds = frameInterval(m_currentFrameNumber);
+
+    if (CCProxy::hasImplThread() && m_currentFrameNumber > 0) {
+        double drawDelayMs = frameIntervalSeconds * 1000.0;
+        WebKit::Platform::current()->histogramCustomCounts("Renderer4.CompositorThreadImplDrawDelay", static_cast<int>(drawDelayMs), 1, 120, 60);
+    }
+
+    if (!isBadFrameInterval(frameIntervalSeconds) && frameIntervalSeconds > kDroppedFrameTime)
+        ++m_droppedFrameCount;
+}
+
+void CCFrameRateCounter::markEndOfFrame()
+{
+    m_currentFrameNumber += 1;
+}
+
+bool CCFrameRateCounter::isBadFrameInterval(double intervalBetweenConsecutiveFrames) const
+{
+    bool schedulerAllowsDoubleFrames = !CCProxy::hasImplThread();
+    bool intervalTooFast = schedulerAllowsDoubleFrames && intervalBetweenConsecutiveFrames < kFrameTooFast;
+    bool intervalTooSlow = intervalBetweenConsecutiveFrames > kFrameTooSlow;
+    return intervalTooFast || intervalTooSlow;
+}
+
+bool CCFrameRateCounter::isBadFrame(int frameNumber) const
+{
+    return isBadFrameInterval(frameInterval(frameNumber));
+}
+
+void CCFrameRateCounter::getAverageFPSAndStandardDeviation(double& averageFPS, double& standardDeviation) const
+{
+    int frame = m_currentFrameNumber - 1;
+    averageFPS = 0;
+    int averageFPSCount = 0;
+    double fpsVarianceNumerator = 0;
+
+    // Walk backwards through the samples looking for a run of good frame
+    // timings from which to compute the mean and standard deviation.
+    //
+    // Slow frames occur just because the user is inactive, and should be
+    // ignored. Fast frames are ignored if the scheduler is in single-thread
+    // mode in order to represent the true frame rate in spite of the fact that
+    // the first few swapbuffers happen instantly which skews the statistics
+    // too much for short lived animations.
+    //
+    // isBadFrame encapsulates the frame too slow/frame too fast logic.
+    while (1) {
+        if (!isBadFrame(frame)) {
+            averageFPSCount++;
+            double secForLastFrame = m_timeStampHistory[frameIndex(frame)] -
+                                     m_timeStampHistory[frameIndex(frame - 1)];
+            double x = 1.0 / secForLastFrame;
+            double deltaFromAverage = x - averageFPS;
+            // Change with caution - numerics. http://en.wikipedia.org/wiki/Standard_deviation
+            averageFPS = averageFPS + deltaFromAverage / averageFPSCount;
+            fpsVarianceNumerator = fpsVarianceNumerator + deltaFromAverage * (x - averageFPS);
+        }
+        if (averageFPSCount && isBadFrame(frame)) {
+            // We've gathered a run of good samples, so stop.
+            break;
+        }
+        --frame;
+        if (frameIndex(frame) == frameIndex(m_currentFrameNumber) || frame < 0) {
+            // We've gone through all available historical data, so stop.
+            break;
+        }
+    }
+
+    standardDeviation = sqrt(fpsVarianceNumerator / averageFPSCount);
+}
+
+double CCFrameRateCounter::timeStampOfRecentFrame(int n)
+{
+    ASSERT(n >= 0 && n < kTimeStampHistorySize);
+    int desiredIndex = (frameIndex(m_currentFrameNumber) + n) % kTimeStampHistorySize;
+    return m_timeStampHistory[desiredIndex];
+}
+
+} // namespace cc
+
+#endif // USE(ACCELERATED_COMPOSITING)