1473376 - MotionMark Leaves benchmark spends a huge amount of time inside regions

Status: RESOLVED FIXED

(Core :: Web Painting, enhancement)

Description

[Bas Schouten (:bas.schouten)]

This is due to accumulating a precise hit testing region for many different small elements. This causes an immensely complex region to build up. Limiting the size of the region is probably a good idea.

Comment 1

[Bas Schouten (:bas.schouten)]

Attachment: Bug 1473376: Ensure hit test regions never grow excessively complex.

Review commit: https://reviewboard.mozilla.org/r/254786/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/254786/

Comment 2

[Kartikaya Gupta (email:[e-mail])]

Comment on attachment 8989826 [details]
Bug 1473376: Ensure hit test regions never grow excessively complex.

https://reviewboard.mozilla.org/r/254786/#review261692

If my reading of the code is correct, even with this patch we could end up with dispatch-to-content regions that have up to 26 rects. The d-t-c region gets simplified to a max of 8 rects in FinishPaintedLayerData, and then if each of the no-action, pan-x, and pan-y regions were super complex, they'd get simplified to 6 rects and added to the d-t-c region. So 8 + (3 * 6) = 26. And actually maybe some more coming from the maybe-hit region, when we create the EventRegions object.

It might be better to simplify the aImpreciseTargetDest region in this patch as well, after squashing the aPreciseTargetDest into it.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/371c4e53d86d
Ensure hit test regions never grow excessively complex. r=kats

Comment 4

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/371c4e53d86d