1976898 - 2.24% vpl-av1 lastFrame (Linux) regression on Thu July 3 2025

Status: RESOLVED WONTFIX

(Core :: Privacy: Anti-Tracking, defect, P3)

Description

[Treeherder Bug Filer]

Perfherder has detected a browsertime performance regression from push 5de6d3b62d9ccca86940fe161e3f0b04401dc93e. As author of one of the patches included in that push, we need your help to address this regression.

Please acknowledge, and begin investigating this alert within 3 business days, or the patch(es) may be backed out in accordance with our regression policy. Our guide to handling regression bugs has information about how you can proceed with this investigation.

If you have any questions or need any help with the investigation, please reach out to [e-mail]. Alternatively, you can find help on Slack by joining #perf-help, and on Matrix you can find help by joining #perftest.

Regressions:

Ratio	Test	Platform	Options	Absolute values (old vs new)	Performance Profiles
2%	vpl-av1 lastFrame	linux1804-64-shippable-qr	cold fission webrender	1,135.85 -> 1,161.35	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.

If you need the profiling jobs you can trigger them yourself from treeherder job view or ask [e-mail] to do that for you.

You can run all of these tests on try with ./mach try perf --alert 45878

The following documentation link provides more information about this command.

Comment 1

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

Set release status flags based on info from the regressing bug 1974449

Comment 2

[Dianna Smith [:diannaS]]

:timhuang can you set a priority/severity for this?

Comment 3

[Emma Zühlcke [:emz]]

The regressor identified adds a migration which runs lazy on startup. It doesn't block anything and only performs a few pref checks / writes. We can't really optimize this further so I'm inclined to WONTFIX here, unless anybody has a better suggestion.