1677872 - Reduce division usage in brush shaders

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, enhancement)

Description

[Lee Salzman [:lsalzman]]

We use mod() in a lot of places in the brush shaders which can generate expensive divisions. If we normalize UVs in the vertex shader, that allows us to use fract() in the fragment shader which is much cheaper.

Comment 1

[Lee Salzman [:lsalzman]]

Attachment: Bug 1677872 - reduce division usage in brush shaders. r?jrmuizel

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/029ac94eb369
reduce division usage in brush shaders. r=gw

Comment 3

[Atila Butkovits]

Backed out for failure at tiled-gradients.html.

Backout link: https://hg.mozilla.org/integration/autoland/rev/080ae9c0fab92d4051f1674dda2f74efb4699c63

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&selectedTaskRun=f7lEcBsASbOyFfl26kRTow.0&resultStatus=testfailed%2Cbusted%2Cexception&revision=029ac94eb36954d8966a86184ea22017d7bcd125&searchStr=wr

Failure log: https://treeherder.mozilla.org/logviewer?job_id=322148605&repo=autoland&lineNumber=7341

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/fc06dd6899fc
reduce division usage in brush shaders. r=gw

Comment 5

[Cristina Coroiu [:ccoroiu]]

Backed out changeset fc06dd6899fc (bug 1677872) for Wr failures at css/css-images/tiled-gradients.html

Backout: https://hg.mozilla.org/integration/autoland/rev/c83082b4ff30056d2c63677d9f25f45a606b6569

Failure push: https://treeherder.mozilla.org/jobs?repo=autoland&revision=fc06dd6899fc727d31610f98a5d0eda989164c8a

Failure log: https://treeherder.mozilla.org/logviewer?job_id=322194484&repo=autoland&lineNumber=8786

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/87753e6e544e
reduce division usage in brush shaders. r=gw

Comment 7

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/87753e6e544ed95d45322c0834af3322572540f2

Comment 8

[Alexandru Ionescu (needinfo me) [:alexandrui]]

== Change summary for alert #27822 (as of Mon, 23 Nov 2020 12:02:50 GMT) ==

Improvements:

Ratio	Suite	Test	Platform	Options	Absolute values (old vs new)
5%	rasterflood_gradient		windows10-64-shippable-qr	e10s stylo webrender-sw	195.29 -> 204.92
5%	rasterflood_gradient		linux64-shippable-qr	e10s stylo webrender-sw	206.58 -> 216.67
5%	rasterflood_gradient		windows10-64-shippable-qr	e10s stylo webrender-sw	195.50 -> 204.75

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=27822