Bug 88464 – Cache isSelfPaintingLayer() for better performance

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[Julien Chaffraix]

Currently we recompute isSelfPaintingLayer() every time the function is called. I have seen this function showing up on some benchmarks when scrolling on big tables such as http://dglazkov.github.com/performance-tests/biggrid.html.

The painting code checks this boolean several time per paint phase so it should help both the self-painting and the non-self-painting layers.

Patch forthcoming.

[Julien Chaffraix]

Created attachment 146132 [details]
Proposed change.

[James Robinson]

Comment on attachment 146132 [details]
Proposed change.

View in context: https://bugs.webkit.org/attachment.cgi?id=146132&action=review

> Source/WebCore/rendering/RenderLayer.cpp:4667
>          || renderer()->hasReflection()

can this change after the RenderLayer is created?

[Simon Fraser (smfr)]

Comment on attachment 146132 [details]
Proposed change.

Seems like hasMask() could also change, as well as some of the isNormalFlowOnly() criteria.

[Simon Fraser (smfr)]

You could cache it between styleChanged() calls maybe.

[James Robinson]

Ah, I see you've hooked styleChanged.

[Simon Fraser (smfr)]

Comment on attachment 146132 [details]
Proposed change.

Oh, I see you update it in styleChanged(). Should be OK. I guess you could assert that m_isSelfPaintingLayer == shouldBeSelfPaintingLayer() in painting, but that's probably overkill.

[Julien Chaffraix]

Please no fighting, style change is covered! :)

(In reply to comment #6)
> (From update of attachment 146132 [details])
> Oh, I see you update it in styleChanged(). Should be OK. I guess you could assert that m_isSelfPaintingLayer == shouldBeSelfPaintingLayer() in painting, but that's probably overkill.

It's possible but if this were to happen I would expect a lot of the code to break pretty badly (it would mean we start mutating the style without notifying us). Also shouldBeNormalFlowOnly has been working pretty well for some time without bug that I know of.

[WebKit Review Bot]

Comment on attachment 146132 [details]
Proposed change.

Clearing flags on attachment: 146132

Committed r119676: <http://trac.webkit.org/changeset/119676>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.