tree 4beac796cef0ce3d6278985c0728478fd8a43622
parent abaef86f2b37d8a939506a2076da07f6db456951
author yunchao.he <yunchao.he@intel.com> 1410746344 -0700
committer Commit bot <commit-bot@chromium.org> 1410746344 -0700

Picture Recording: fix the performance bottleneck in SkDeferredCanvas::isFullFrame

blink skips all pending commands during picture recording if it is drawing an opaque full-frame
geometry or image. This may improve performance for some edge cases. To recognize an opaque
full-frame drawing should be cheap enough. Otherwise, the overhead will offset the improvement.
Unfortunately, data from perf for content_shell on Nexus7 shows that SkDeferredCanvas::isFullFrame
is far from cheap. Table below shows that how much isFullFrame() costs in the whole render process.

benchmark                              percentage
my local benchmark(draw 1000 sprites)   4.1%
speedReading                            2.8%
FishIETank(1000 fishes)                 1.5%
GUIMark3 Bitmap                         2.0%

By contrast, real recording (SkGPipeCanvas::drawBitmapRectToRect) and real rasterization
(GrDrawTarget::drawRect) cost ~4% and ~6% in the whole render process respectively. Apparently,
SkDeferredCanvas::isFullFrame() is nontrivial.

getDeviceSize() is the main contributor to this hotspot. The change simply save the canvasSize and
reuse it among drawings if it is not a fresh frame. This change cut off ~65% (or improved ~2 times)
of isFullFrame().

telemetry smoothness canvas_tough_test didn't show obvious improvement or regression.

BUG=411166
R=junov@chromium.org, tomhudson@google.com, reed@google.com

Author: yunchao.he@intel.com

Review URL: https://codereview.chromium.org/545813002