1886739 - Give position: sticky items their own picture cache slice

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, task)

Description

[Jamie Nicol [:jnicol]]

When a position: sticky element is "stuck" and its sibling content is scrolling underneath it, this causes unnecessary amounts of invalidation leading to slow render times. We should give the sticky items their own picture cache slice.

https://blog.mozilla.org/en/category/products/firefox/ is a good example. The header bar is position: sticky and if you enable gfx.webrender.debug.picture-caching you can see the top row of tiles are constantly invalidating whilst scrolling.

Comment 1

[Jamie Nicol [:jnicol]]

Attachment: Bug 1886739 - Give position: sticky items their own picture cache slice

position: sticky items scroll independently of their containing
content, resulting in large amounts of picture cache invalidation when
scrolling, causing poor performance. This patch attempts to give them
their own picture cache slice in order to avoid that invalidation.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d5a2008c802b
Give position: sticky items their own picture cache slice r=gfx-reviewers,gw

Comment 3

[Norisz Fay [:noriszfay]]

Backed out for causing multiple failures

Backout link

Push with failures

Failure log // Failure log 2 // Failure log 3

Comment 4

[Jamie Nicol [:jnicol]]

Whoops, need to fuzz a few tests on android

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/50f38f0452e3
Give position: sticky items their own picture cache slice r=gfx-reviewers,gw

Comment 6

[Cristian Tuns]

https://hg.mozilla.org/mozilla-central/rev/50f38f0452e3

Comment 7

[Donal Meehan [:dmeehan]]

Backed out of release for causing Bug 1895585
Backout Link: https://hg.mozilla.org/releases/mozilla-release/rev/9628359c3a69dea9f91219ad58a95a0ffb8e7359