1602361 - Scrolling in pages with scrollable content on some websites is very slow when WebRender (with compositor) is enabled on macOS

Status: RESOLVED INVALID

(Core :: Graphics: WebRender, defect, P3)

Description

[Haonan Yu]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:73.0) Gecko/20100101 Firefox/73.0

Steps to reproduce:

Firefox version: 73.0a1 (2019-12-08) (64-bit)
OS version: macOS 10.15.1(19B2106)
GPU: Integrated GPU(Intel)

prefs:

gfx.webrender.all	                true
gfx.webrender.all.qualified	true
gfx.webrender.compositor	true
gfx.webrender.enabled          true

1. Open https://askubuntu.com/questions/1189049/ubuntu-18-04-3-lts-kernel-5-0-0-25-generic-nvidia-driver-440-not-working-with-gr
2. Scroll the small scrollable content first
3. Scroll the entire page

A screen recording to reproduce this: https://youtu.be/AwudKSppFNg

Actual results:

When scrolling the entire page, page stuck for a short time(even when this What did you do? input is scrollable)

Expected results:

Scrolling should be as fluent as normal browsing.

Comment 1

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

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Comment 2

[Miko Mynttinen]

Haonan Yu, could you attach the content of your about:support?

This might be related to the other Intel compositor bugs we've seen recently.

Comment 3

[Miko Mynttinen]

I was not able to reproduce this with Nightly (20191213094653) running on MBP with Intel UHD Graphics 630.

Comment 4

[Haonan Yu]

Attachment: about:support content

Hi,
Sorry for my late response. I upgraded to Nightly (2019-12-15) and I found scrolling is smoother than old version. However I noticed scrolling over small scrollable content is a little laggy. I tested with a fresh new profile and it's still laggy. Here are my about:support configs:

```

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