1980980 - 24.67 - 5.86% twitter fcp / vpl-av1 posterEnd + 5 more (Android, Linux, OSX) regression on Fri July 25 2025

Status: RESOLVED INVALID

(Core :: JavaScript: GC, defect)

Description

[Treeherder Bug Filer]

Perfherder has detected a browsertime performance regression from push 41f6c3d3c129150be0fc865b162278bbaeb65d90. 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
25%	twitter fcp	macosx1470-64-shippable	bytecode-cached cold fission webrender	90.27 -> 112.54	Before/After
23%	twitter fcp	macosx1470-64-shippable	cold fission webrender	92.35 -> 113.53	Before/After
22%	twitter FirstVisualChange	macosx1470-64-shippable	bytecode-cached cold fission webrender	114.47 -> 140.02	Before/After
16%	instagram FirstVisualChange	macosx1470-64-shippable	bytecode-cached cold fission webrender	141.27 -> 163.95	Before/After
15%	google-mail LastVisualChange	linux1804-64-shippable-qr	fission warm webrender	1,136.24 -> 1,308.11	Before/After
6%	vpl-av1 estimatedFirstFrameLatency	android-hw-a55-14-0-aarch64-shippable	cold fission webrender	454.75 -> 481.41	Before/After
6%	vpl-av1 posterEnd	android-hw-a55-14-0-aarch64-shippable	cold fission webrender	454.75 -> 481.41	Before/After

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)	Performance Profiles
11%	youtube loadtime	linux1804-64-shippable-qr	cold fission webrender	1,796.18 -> 1,605.07	Before/After
4%	speedometer VueJS-TodoMVC/Adding100Items/Sync	macosx1500-aarch64-shippable	fission webrender	0.65 -> 0.62
3%	speedometer EmberJS-Debug-TodoMVC/CompletingAllItems/Sync	windows11-64-24h2-shippable	fission webrender	89.08 -> 86.60
3%	speedometer EmberJS-Debug-TodoMVC/CompletingAllItems	windows11-64-24h2-shippable	fission webrender	90.84 -> 88.35

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 46072

The following documentation link provides more information about this command.

Comment 1

[Jan de Mooij [:jandem]]

The revision in comment 0 is for an Android change?

Comment 2

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

Set release status flags based on info from the regressing bug 1977367

Comment 3

[Alex Finder]

(In reply to Jan de Mooij [:jandem] from comment #1)

The revision in comment 0 is for an Android change?

Hi Jan! Thanks for the ni, you're right! After retriggering, it seems that the culprit is actually 36fb219b5e5fe9c5ee71a0a519915c82610ae1cd. I'll close this bug as INVALID and reassign the alerts to alert summary id 46079, which has bug id 1981377 linked to it.