Improved heuristic for disable acceleration.

third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp

Index: third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp
diff --git a/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp b/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp
index baa008606aa270dee1285506c565e58a9ef0362e..b20cbe4f00700f2184fdb1059d09196eef4df2f0 100644
--- a/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp
+++ b/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp
@@ -53,7 +53,6 @@
 #include "modules/canvas2d/Path2D.h"
 #include "platform/fonts/FontCache.h"
 #include "platform/graphics/DrawLooperBuilder.h"
-#include "platform/graphics/ExpensiveCanvasHeuristicParameters.h"
 #include "platform/graphics/ImageBuffer.h"
 #include "platform/graphics/StrokeData.h"
 #include "platform/graphics/skia/SkiaUtils.h"
@@ -1068,30 +1067,69 @@ unsigned CanvasRenderingContext2D::hitRegionsCount() const
     return 0;
 }
 
+
+double CanvasRenderingContext2D::estimateRenderingCostForUsage(BaseRenderingContext2D::UsageCounters usage, ExpensiveCanvasHeuristicParameters::RenderingModeCostIndex index) const

[Justin Novosad, 2016/08/04 15:53:17]

double -> float   here and below

[sebastienlc, 2016/08/04 16:36:27]

Done.

+{
+    double basicCostOfDrawCalls =
+        ExpensiveCanvasHeuristicParameters::FillRectFixedCost[index] * usage.numDrawCalls[BaseRenderingContext2D::FillRect] +
+        ExpensiveCanvasHeuristicParameters::FillConvexPathFixedCost[index] * (usage.numDrawCalls[BaseRenderingContext2D::FillPath] - usage.numNonConvexFillPathCalls) +
+        ExpensiveCanvasHeuristicParameters::FillNonConvexPathFixedCost[index] * usage.numNonConvexFillPathCalls +
+        ExpensiveCanvasHeuristicParameters::FillTextFixedCost[index] * usage.numDrawCalls[BaseRenderingContext2D::FillText] +
+
+        ExpensiveCanvasHeuristicParameters::StrokeRectFixedCost[index] * usage.numDrawCalls[BaseRenderingContext2D::StrokeRect] +
+        ExpensiveCanvasHeuristicParameters::StrokePathFixedCost[index] * usage.numDrawCalls[BaseRenderingContext2D::StrokePath] +
+        ExpensiveCanvasHeuristicParameters::StrokeTextFixedCost[index] * usage.numDrawCalls[BaseRenderingContext2D::StrokeText] +
+
+        ExpensiveCanvasHeuristicParameters::FillRectVariableCostPerArea[index] * usage.boundingBoxAreaDrawCalls[BaseRenderingContext2D::FillRect] +
+        ExpensiveCanvasHeuristicParameters::FillConvexPathVariableCostPerArea[index] * (usage.boundingBoxAreaDrawCalls[BaseRenderingContext2D::FillPath] - usage.nonConvexFillPathArea) +
+        ExpensiveCanvasHeuristicParameters::FillNonConvexPathVariableCostPerArea[index] * usage.nonConvexFillPathArea +
+        ExpensiveCanvasHeuristicParameters::FillTextVariableCostPerArea[index] * usage.boundingBoxAreaDrawCalls[BaseRenderingContext2D::FillText] +
+
+        ExpensiveCanvasHeuristicParameters::StrokeRectVariableCostPerArea[index] * usage.boundingBoxAreaDrawCalls[BaseRenderingContext2D::StrokeRect] +
+        ExpensiveCanvasHeuristicParameters::StrokePathVariableCostPerArea[index] * usage.boundingBoxAreaDrawCalls[BaseRenderingContext2D::StrokePath] +
+        ExpensiveCanvasHeuristicParameters::StrokeTextVariableCostPerArea[index] * usage.boundingBoxAreaDrawCalls[BaseRenderingContext2D::StrokeText] +
+
+        ExpensiveCanvasHeuristicParameters::PutImageDataFixedCost[index] * usage.numPutImageDataCalls +
+        ExpensiveCanvasHeuristicParameters::PutImageDataVariableCostPerArea[index] * usage.areaPutImageDataCalls +
+
+        ExpensiveCanvasHeuristicParameters::DrawSVGImageFixedCost[index] * usage.numDrawCalls[BaseRenderingContext2D::DrawSVGImage] +
+        ExpensiveCanvasHeuristicParameters::DrawPNGImageFixedCost[index] * usage.numDrawCalls[BaseRenderingContext2D::DrawPNGImage] +
+
+        ExpensiveCanvasHeuristicParameters::DrawSVGImageVariableCostPerArea[index] * usage.boundingBoxAreaDrawCalls[BaseRenderingContext2D::DrawSVGImage] +
+        ExpensiveCanvasHeuristicParameters::DrawPNGImageVariableCostPerArea[index] * usage.boundingBoxAreaDrawCalls[BaseRenderingContext2D::DrawPNGImage];
+
+    double fillTypeAdjustment =
+        ExpensiveCanvasHeuristicParameters::PatternFillTypeFixedCost[index] * usage.numPatterns +
+        ExpensiveCanvasHeuristicParameters::LinearGradientFillTypeFixedCost[index] * usage.numLinearGradients +
+        ExpensiveCanvasHeuristicParameters::RadialGradientFillTypeFixedCost[index] * usage.numRadialGradients +
+
+        ExpensiveCanvasHeuristicParameters::PatternFillTypeVariableCostPerArea[index] * usage.boundingBoxAreaFillType[BaseRenderingContext2D::PatternFillType] +
+        ExpensiveCanvasHeuristicParameters::LinearGradientFillVariableCostPerArea[index] * usage.boundingBoxAreaFillType[BaseRenderingContext2D::LinearGradientFillType] +
+        ExpensiveCanvasHeuristicParameters::RadialGradientFillVariableCostPerArea[index] * usage.boundingBoxAreaFillType[BaseRenderingContext2D::RadialGradientFillType];
+
+    double shadowAdjustment =
+        ExpensiveCanvasHeuristicParameters::ShadowFixedCost[index] * usage.numBlurredShadows +
+        ExpensiveCanvasHeuristicParameters::ShadowVariableCostPerAreaTimesShadowBlurSquared[index] * usage.boundingBoxAreaTimesShadowBlurSquared;
+
+    return basicCostOfDrawCalls + fillTypeAdjustment + shadowAdjustment;
+}
+
 bool CanvasRenderingContext2D::isAccelerationOptimalForCanvasContent() const
 {
-    // Simple heuristic to determine if the GPU accelerated pipeline should be
-    // used to maximize performance of 2D canvas based on past usage.
+    // Heuristic to determine if the GPU accelerated rendering pipeline is optimal
+    // for performance based on past usage. It has a bias towards suggesting that the
+    // accelerated pipeline is optimal.
 
-    int numDrawPathCalls =
-        m_usageCounters.numDrawCalls[StrokePath] +
-        m_usageCounters.numDrawCalls[FillPath] +
-        m_usageCounters.numDrawCalls[FillText] +
-        m_usageCounters.numDrawCalls[StrokeText] +
-        m_usageCounters.numDrawCalls[FillRect] +
-        m_usageCounters.numDrawCalls[StrokeRect];
+    double acceleratedCost = estimateRenderingCostForUsage(m_usageCounters, ExpensiveCanvasHeuristicParameters::AcceleratedModeIndex);

[Justin Novosad, 2016/08/04 15:53:17]

double -> float here and below

[sebastienlc, 2016/08/04 16:36:27]

Done.

 
-    double acceleratedCost =
-        numDrawPathCalls * ExpensiveCanvasHeuristicParameters::AcceleratedDrawPathApproximateCost +
-        m_usageCounters.numGetImageDataCalls * ExpensiveCanvasHeuristicParameters::AcceleratedGetImageDataApproximateCost+
-        m_usageCounters.numDrawCalls[DrawImage] * ExpensiveCanvasHeuristicParameters::AcceleratedDrawImageApproximateCost;
+    double recordingCost = estimateRenderingCostForUsage(m_usageCounters, ExpensiveCanvasHeuristicParameters::RecordingModeIndex);
 
-    double recordingCost =
-        numDrawPathCalls * ExpensiveCanvasHeuristicParameters::RecordingDrawPathApproximateCost +
-        m_usageCounters.numGetImageDataCalls * ExpensiveCanvasHeuristicParameters::UnacceleratedGetImageDataApproximateCost +
-        m_usageCounters.numDrawCalls[DrawImage] * ExpensiveCanvasHeuristicParameters::RecordingDrawImageApproximateCost;
+    double costDifference = acceleratedCost - recordingCost;
+    double percentCostReduction = costDifference / acceleratedCost * 100.0;
+    double costDifferencePerFrame = costDifference / m_usageCounters.numFramesSinceReset;
 
-    if (recordingCost * ExpensiveCanvasHeuristicParameters::AcceleratedHeuristicBias < acceleratedCost) {
+    if (percentCostReduction >= ExpensiveCanvasHeuristicParameters::MinPercentageImprovementToSuggestDisableAcceleration
+        && costDifferencePerFrame >= ExpensiveCanvasHeuristicParameters::MinCostPerFrameImprovementToSuggestDisableAcceleration) {
         return false;
     }
     return true;