1852584 - 196.83 - 15.84% tp5o_scroll / tp5o_webext responsiveness + 3 more (Linux) regression on Tue September 5 2023

Status: RESOLVED FIXED

(Core :: Widget: Gtk, defect)

Description

[Andrej (:aglavic)]

Perfherder has detected a talos performance regression from push a7ce0ac3a970b859d080e757b733ada1001c5328. As author of one of the patches included in that push, we need your help to address this regression.

Regressions:

Ratio	Test	Platform	Options	Absolute values (old vs new)
197%	tp5o_scroll	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	2.04 -> 6.07
28%	tp5o_scroll	linux1804-64-shippable-qr	e10s fission stylo webrender	2.86 -> 3.67
20%	tp5o_webext responsiveness	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	3.38 -> 4.06
17%	twinopen ext+twinopen:twinopen.html	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	121.21 -> 142.35
16%	tp5o_webext responsiveness	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	3.43 -> 3.97

Details of the alert can be found in the alert summary, including links to graphs and comparisons for each of the affected tests. Please follow our guide to handling regression bugs and let us know your plans within 3 business days, or the offending patch(es) may be backed out in accordance with our regression policy.

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Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1852584 - Disable rounded bottom corners for performance regressions for now. r=stransky

Comment 2

[Emilio Cobos Álvarez (:emilio)]

Glenn, do you know why a clip in the parent process regresses performance so much? Any hints for how to tackle this / best implement this?

Given this and the backdrop-filter correctness issue, we should probably disable for now, but would be nice to fix this properly.

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Specially for software webrender, this seems like a massive regression :/

Comment 4

[Emilio Cobos Álvarez (:emilio)]

Lee, in case you can take a look, any hints?

Comment 5

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

Set release status flags based on info from the regressing bug 1850827

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d716a9757780
Disable rounded bottom corners for performance regressions for now. r=stransky

Comment 8

[Glenn Watson [:gw]]

I don't know what would cause a regression like that, is it possible to get a profile with/without pasted?

My initial guess is that once we have rounded corners on the parent we no longer detect that the background tiles are occluded, and that we probably then composite a lot more pixels, which would especially hurt SWGL. That's just a guess though. It's probably something we can mitigate with slightly smarter picture caching logic.

Comment 9

[Glenn Watson [:gw]]

Or perhaps that we treat all the background tiles as transparent, once we see that there is a clip mask on them, I wonder.

Comment 10

[Glenn Watson [:gw]]

Oh, I just also noticed, looking at something unrelated (https://bugzilla.mozilla.org/show_bug.cgi?id=1849680) that this causes google maps to not get a compositor surface on Linux, which will also hurt performance on a number of pages. I'll be working to support this use case in the linked bug.

Comment 11

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/d716a9757780

Comment 12

[Andrej (:aglavic)]

== Change summary for alert #39591 (as of Mon, 18 Sep 2023 18:00:55 GMT) ==

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)
67%	tp5o_scroll	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	6.11 -> 2.02
67%	tp5o_scroll	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	6.09 -> 2.03
25%	tp5o_scroll	linux1804-64-shippable-qr	e10s fission stylo webrender	3.61 -> 2.71
19%	tp5o_webext responsiveness	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	4.30 -> 3.48
13%	twinopen ext+twinopen:twinopen.html	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	142.84 -> 123.75

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=39591(In reply to Pulsebot from comment #7)

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d716a9757780
Disable rounded bottom corners for performance regressions for now.
r=stransky

Your changes look to have reverted the regression!