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| 1 // Copyright 2012 The Chromium Authors. All rights reserved. | 1 // Copyright 2012 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 #ifndef CCFrameRateCounter_h | 5 #ifndef CCFrameRateCounter_h |
| 6 #define CCFrameRateCounter_h | 6 #define CCFrameRateCounter_h |
| 7 | 7 |
| 8 #include "base/basictypes.h" | 8 #include "base/basictypes.h" |
| 9 #include "base/memory/scoped_ptr.h" | 9 #include "base/memory/scoped_ptr.h" |
| 10 #include "base/time.h" | 10 #include "base/time.h" |
| 11 | 11 |
| 12 namespace cc { | 12 namespace cc { |
| 13 | 13 |
| 14 // This class maintains a history of timestamps, and provides functionality to | 14 // This class maintains a history of timestamps, and provides functionality to |
| 15 // intelligently compute average frames per second (and standard deviation). | 15 // intelligently compute average frames per second (and standard deviation). |
| 16 class FrameRateCounter { | 16 class FrameRateCounter { |
| 17 public: | 17 public: |
| 18 static scoped_ptr<FrameRateCounter> create(); | 18 static scoped_ptr<FrameRateCounter> create(bool hasImplThread); |
| 19 | 19 |
| 20 void markBeginningOfFrame(base::TimeTicks timestamp); | 20 void markBeginningOfFrame(base::TimeTicks timestamp); |
| 21 void markEndOfFrame(); | 21 void markEndOfFrame(); |
| 22 int currentFrameNumber() const { return m_currentFrameNumber; } | 22 int currentFrameNumber() const { return m_currentFrameNumber; } |
| 23 void getAverageFPSAndStandardDeviation(double& averageFPS, double& standardD
eviation) const; | 23 void getAverageFPSAndStandardDeviation(double& averageFPS, double& standardD
eviation) const; |
| 24 int timeStampHistorySize() const { return kTimeStampHistorySize; } | 24 int timeStampHistorySize() const { return kTimeStampHistorySize; } |
| 25 | 25 |
| 26 // n = 0 returns the oldest frame retained in the history, | 26 // n = 0 returns the oldest frame retained in the history, |
| 27 // while n = timeStampHistorySize() - 1 returns the timestamp most recent fr
ame. | 27 // while n = timeStampHistorySize() - 1 returns the timestamp most recent fr
ame. |
| 28 base::TimeTicks timeStampOfRecentFrame(int n); | 28 base::TimeTicks timeStampOfRecentFrame(int n); |
| 29 | 29 |
| 30 // This is a heuristic that can be used to ignore frames in a reasonable way
. Returns | 30 // This is a heuristic that can be used to ignore frames in a reasonable way
. Returns |
| 31 // true if the given frame interval is too fast or too slow, based on consta
nt thresholds. | 31 // true if the given frame interval is too fast or too slow, based on consta
nt thresholds. |
| 32 bool isBadFrameInterval(base::TimeDelta intervalBetweenConsecutiveFrames) co
nst; | 32 bool isBadFrameInterval(base::TimeDelta intervalBetweenConsecutiveFrames) co
nst; |
| 33 | 33 |
| 34 int droppedFrameCount() const { return m_droppedFrameCount; } | 34 int droppedFrameCount() const { return m_droppedFrameCount; } |
| 35 | 35 |
| 36 private: | 36 private: |
| 37 FrameRateCounter(); | 37 explicit FrameRateCounter(bool hasImplThread); |
| 38 | 38 |
| 39 base::TimeDelta frameInterval(int frameNumber) const; | 39 base::TimeDelta frameInterval(int frameNumber) const; |
| 40 int frameIndex(int frameNumber) const; | 40 int frameIndex(int frameNumber) const; |
| 41 bool isBadFrame(int frameNumber) const; | 41 bool isBadFrame(int frameNumber) const; |
| 42 | 42 |
| 43 // Two thresholds (measured in seconds) that describe what is considered to
be a "no-op frame" that should not be counted. | 43 // Two thresholds (measured in seconds) that describe what is considered to
be a "no-op frame" that should not be counted. |
| 44 // - if the frame is too fast, then given our compositor implementation, the
frame probably was a no-op and did not draw. | 44 // - if the frame is too fast, then given our compositor implementation, the
frame probably was a no-op and did not draw. |
| 45 // - if the frame is too slow, then there is probably not animating content,
so we should not pollute the average. | 45 // - if the frame is too slow, then there is probably not animating content,
so we should not pollute the average. |
| 46 static const double kFrameTooFast; | 46 static const double kFrameTooFast; |
| 47 static const double kFrameTooSlow; | 47 static const double kFrameTooSlow; |
| 48 | 48 |
| 49 // If a frame takes longer than this threshold (measured in seconds) then we | 49 // If a frame takes longer than this threshold (measured in seconds) then we |
| 50 // (naively) assume that it missed a screen refresh; that is, we dropped a f
rame. | 50 // (naively) assume that it missed a screen refresh; that is, we dropped a f
rame. |
| 51 // FIXME: Determine this threshold based on monitor refresh rate, crbug.com/
138642. | 51 // FIXME: Determine this threshold based on monitor refresh rate, crbug.com/
138642. |
| 52 static const double kDroppedFrameTime; | 52 static const double kDroppedFrameTime; |
| 53 | 53 |
| 54 static const int kTimeStampHistorySize = 120; | 54 static const int kTimeStampHistorySize = 120; |
| 55 | 55 |
| 56 bool m_hasImplThread; |
| 57 |
| 56 int m_currentFrameNumber; | 58 int m_currentFrameNumber; |
| 57 base::TimeTicks m_timeStampHistory[kTimeStampHistorySize]; | 59 base::TimeTicks m_timeStampHistory[kTimeStampHistorySize]; |
| 58 | 60 |
| 59 int m_droppedFrameCount; | 61 int m_droppedFrameCount; |
| 60 | 62 |
| 61 DISALLOW_COPY_AND_ASSIGN(FrameRateCounter); | 63 DISALLOW_COPY_AND_ASSIGN(FrameRateCounter); |
| 62 }; | 64 }; |
| 63 | 65 |
| 64 } // namespace cc | 66 } // namespace cc |
| 65 | 67 |
| 66 #endif | 68 #endif |
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