2001630 - 24.68% google-search LastVisualChange (Linux) regression on Tue November 18 2025

Status: RESOLVED FIXED

(Firefox :: Address Bar, defect, P1)

Description

[Treeherder Bug Filer]

Perfherder has detected a browsertime performance regression from push 073211ebd95aed914a7d7f1913316ddec4d76b02. 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%	google-search LastVisualChange	linux1804-64-shippable-qr	fission warm webrender	448.46 -> 559.13	Before/After

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)	Performance Profiles
10%	google-search LastVisualChange	linux1804-64-shippable-qr	cold fission webrender	831.05 -> 751.51	Before/After
7%	bing-search ContentfulSpeedIndex	linux1804-64-shippable-qr	bytecode-cached fission warm webrender	306.52 -> 285.10	Before/After
7%	bing-search ContentfulSpeedIndex	linux1804-64-shippable-qr	fission warm webrender	286.54 -> 267.12	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 47499

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 1997189

Comment 2

[Dale Harvey (:daleharvey)]

Quite confused about how this small change can have such a dramatic effect but will investigate

Comment 3

[Dale Harvey (:daleharvey)]

Attachment: Bug 2001630 - Dont remove identity-box margin without trustpanel enabled. r=dao

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/2ff0e2a114de
https://hg.mozilla.org/integration/autoland/rev/0a027711e43c
Dont remove identity-box margin without trustpanel enabled. r=dao,desktop-theme-reviewers

Comment 5

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/0a027711e43c