1947292 - 8.4 - 2.6% stylebench Before and after pseudo elements/Removing leaf elements - 1 / stylebench Structural pseudo classes/Adding classes - 4 + 5 more (Windows) regression on Tue February 4 2025

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Treeherder Bug Filer]

Perfherder has detected a browsertime performance regression from push 9d8b4c0b99ed4e5f39825c3c8890979ca64efdd8. 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)	Performance Profiles
8%	stylebench Before and after pseudo elements/Removing leaf elements - 1	windows11-64-shippable-qr	fission webrender	9.42 -> 10.21	Before/After
8%	stylebench Descendant and child combinators/Removing classes - 0	windows11-64-shippable-qr	fission webrender	3.11 -> 3.37	Before/After
7%	stylebench Sibling combinators/Adding leaf elements - 2/Async	windows11-64-shippable-qr	fission webrender	16.35 -> 17.43	Before/After
6%	stylebench Descendant and child combinators/Removing classes - 2	windows11-64-shippable-qr	fission webrender	8.33 -> 8.87	Before/After
6%	stylebench Sibling combinators/Adding leaf elements - 2	windows11-64-shippable-qr	fission webrender	17.81 -> 18.83	Before/After
3%	stylebench Nth pseudo classes/Adding classes - 1	windows11-64-shippable-qr	fission webrender	5.94 -> 6.11	Before/After
3%	stylebench Structural pseudo classes/Adding classes - 4	windows11-64-shippable-qr	fission webrender	5.99 -> 6.14	Before/After

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)	Performance Profiles
2%	stylebench Nth pseudo classes/Removing leaf elements - 2	windows11-64-shippable-qr	fission webrender	19.23 -> 18.80	Before/After

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 patch(es) may be backed out in accordance with our regression policy.

If you need the profiling jobs you can trigger them yourself from treeherder job view or ask a sheriff to do that for you.

You can run all of these tests on try with ./mach try perf --alert 43693

The following documentation link provides more information about this command.

For more information on performance sheriffing please see our FAQ.

If you have any questions, please do not hesitate to reach out to [e-mail].

Comment 1

[Acasandrei Beatrice (needinfo me)]

The changes have been backedout, and this bug can be closed. No further action is required from the author.

Comment 2

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

A comment containing a reason for why the performance regression was resolved as FIXED could not be found. It should provided when the status of the bug is changed.

:gw, since you resolved this bug, could you provide a comment explaining the resolution? If one has already been provided, this needinfo can be ignored/removed.

If you need additional information/help, reach out in #perftest, or #perfsheriffs on Element.

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