1592882 - Scrolling on Bugzilla became janky since yesterday

Status: RESOLVED INVALID

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

Description

[Mayank Bansal]

Attachment: aboutsupport.txt

https://perfht.ml/34jyRNU

Go to any bugzilla page, and scroll

Comment 1

[Mayank Bansal]

Also janky on other pages like this : https://perfht.ml/2Jz3FT0
https://www.guru3d.com/

Comment 2

[Mayank Bansal]

regression threw this range:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=25bf8e097e604cca2842af6754c2c1698db5618a&tochange=f67361bfb377d12c0ee1f26f710833f20641bb77

Comment 3

[Nicolas Silva [:nical]]

I don't see obvious suspects in the regression range. The profile shows that we spend an awful amount of time blocking the parent main thread waiting for some synchronous hit testing-related IPC, which would be improved by bug 1580178, there might also be frame scheduling issues making things worse. The threads don't look unreasonably busy.

I'll block this on bug 1580178 but it would be good to understand why this regressed recently.
ni? Botond in case you've seen input related stuff land recently-ish that might be related.

Comment 4

[Timothy Nikkel (:tnikkel)]

Can you regression range is down to a small range?

Comment 5

[Mayank Bansal]

(In reply to Timothy Nikkel (:tnikkel) from comment #4)

Can you regression range is down to a small range?

I tried multiple times, but the mozregression-gui tool fails at this stage.

Comment 6

[Timothy Nikkel (:tnikkel)]

What error does it give?

Comment 7

[Botond Ballo [:botond]]

I don't see anything obvious in the regression range, either, and I can't think of anything in particular that landed recently that might have caused a regression like this.

I also can't reproduce the issue.

Perhaps we could get some help from QA, to try to reproduce the issue, and if so, get a narrower regression range?

Comment 8

[Tania Maity (:tmaity)]

We'll assign a QA member to investigate this further.

Comment 9

[Timea Cernea [:tbabos][inactive]]

Hey Mayank,

I didn't notice any alarming scroll performance on the latest Nightly 2019-11-03.
I have Intel HD Graphics 4600 and enabled WebRender to check it out.

Did you try to disable WebRender and see if it still reproduces?

Comment 10

[Mayank Bansal]

I cannot reproduce it now. Though, when I filed this bug, the scrolling was quite micro-jittery.
Will close this bug now, and reopen if I reproduce this issue.