[webkit-changes] [WebKit/WebKit] 3e7f2c: REGRESSION(274164 at main): Do not consult against Do...

[Yusuke Suzuki]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 3e7f2c1bc01db4255c2de428d4b5d04ab054df86
      https://github.com/WebKit/WebKit/commit/3e7f2c1bc01db4255c2de428d4b5d04ab054df86
  Author: Yusuke Suzuki <ysuzuki at apple.com>
  Date:   2024-02-21 (Wed, 21 Feb 2024)

  Changed paths:
    M Source/WebCore/dom/Document.cpp
    M Source/WebCore/dom/Document.h
    M Source/WebCore/html/CanvasBase.cpp
    M Source/WebCore/html/HTMLCanvasElement.cpp
    M Source/WebCore/html/canvas/CanvasRenderingContext.h

  Log Message:
  -----------
  REGRESSION(274164 at main): Do not consult against Document's WeakHashSet for every Canvas ops
https://bugs.webkit.org/show_bug.cgi?id=269867
rdar://123400342

Reviewed by Ryosuke Niwa.

274164 at main introduced addCanvasNeedingPreparationForDisplayOrFlush and removeCanvasNeedingPreparationForDisplayOrFlush, which consult against Document's WeakHashSet
for every Canvas operation. Because each Canvas operation is very tiny, Canvas operations are called super frequently, and any kind of performance regression on each
call can be exhibited as visible performance regression. WeakHashSet querying is costly, and Document is super large so frequent cache miss happens.
Instead, we store a bool flag to CanvasRenderingContext, which says whether it is registered in Document's WeakHashSet. And avoid this costly operation once it gets registered.

* Source/WebCore/dom/Document.cpp:
(WebCore::Document::prepareCanvasesForDisplayOrFlushIfNeeded):
(WebCore::Document::addCanvasNeedingPreparationForDisplayOrFlush):
(WebCore::Document::removeCanvasNeedingPreparationForDisplayOrFlush):
* Source/WebCore/dom/Document.h:
* Source/WebCore/html/CanvasBase.cpp:
(WebCore::CanvasBase::addCanvasNeedingPreparationForDisplayOrFlush):
(WebCore::CanvasBase::removeCanvasNeedingPreparationForDisplayOrFlush):
* Source/WebCore/html/HTMLCanvasElement.cpp:
(WebCore::HTMLCanvasElement::didMoveToNewDocument):
* Source/WebCore/html/canvas/CanvasRenderingContext.h:
(WebCore::CanvasRenderingContext::setIsToPrepare):
(WebCore::CanvasRenderingContext::isInPreparationForDisplayOrFlush const):

Canonical link: https://commits.webkit.org/275137@main



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