1699042 - on scroll event have a page visual update lag

Status: RESOLVED WORKSFORME

(Core :: Layout, defect)

Description

[Karl Dubost💡 :karlcow]

I'm not sure if it's graphics the issue or if it's because of intense getComputedPosition

1. With Firefox Nightly on Android
2. Go to https://m.hoyolab.com/genshin/#/home/0
3. Then scroll

Expected:
Smooth scrool

Actual:

• Scroll janky
• Layout disappears and then reappears.

Performance issue?
Working fine on chrome.

Comment 1

[Karl Dubost💡 :karlcow]

A profile https://share.firefox.dev/38OFXPv
Check in between 18 and 23s

Comment 2

[Jamie Nicol [:jnicol]]

The renderer thread does appear to be doing anything for the first 2 seconds of that period, which would certainly explain the jank. It's possible that webrender is taking too long further back in the pipeline. Karl, could you take another profile using the "Firefox Graphics" preset?

Could you also try setting gfx.webrender.force-disabled to true, restart, and see if that helps?

Comment 3

[Karl Dubost💡 :karlcow]

Jamie,
Yeah sure.

Firefox Graphics on with two subsequent scrolls.
https://share.firefox.dev/3cRifTE

And indeed setting gfx.webrender.force-disabled to true solves the issue

Comment 4

[Jamie Nicol [:jnicol]]

On desktop with an android user agent set I can't even scroll this page with a mouse/touchpad scroll. Clicking and dragging reproduces the same bug as on android. Have they implemented their own scrolling behaviour??

Mozregression points to this - bug 1656418.

Partial pre-render is currently only enabled on Nightly. Karl, can you confirm that you can only reproduce this on nightly. And does setting layout.animation.prerender.partial=false fix it? It does for me.

Scrolling is still janky but it's like that in Chrome and Firefox both with and without webrender. I'm guessing it's due to whatever way they're implementing the scrolling. The profile shows there's no webrender perf issue here.

Comment 5

[BugBot [:suhaib / :marco/ :calixte]]

The component has been changed since the backlog priority was decided, so we're resetting it.
For more information, please visit auto_nag documentation.

Comment 6

[Karl Dubost💡 :karlcow]

Jamie,

layout.animation.prerender.partial set to false on desktop with RDM on desktop and a Firefox Android UA doesn't fix it for me.
but it fixes it on android device indeed.

Comment 7

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1656418

:hiro, since you are the author of the regressor, bug 1656418, could you take a look?

For more information, please visit auto_nag documentation.

Comment 8

[Hiroyuki Ikezoe (:hiro)]

The pref causes this has already been disabled.

Comment 9

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1656418

Comment 10

[Ksenia Berezina [:ksenia]]

The site design has changed and the issue with scrolling in https://webcompat.com/issues/67703 doesn't seem to be reproducible anymore with or without layout.animation.prerender.partial enabled.