1858601 - 11.78 - 10.22% fandom loadtime / fandom loadtime (Windows) regression on Fri October 6 2023

Status: RESOLVED WONTFIX

(Core :: XPCOM, defect)

Description

[Alexandru Ionescu (needinfo me) [:alexandrui]]

Perfherder has detected a browsertime performance regression from push 107265085a67a702557aba007008b4b22e29c793. 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
12%	fandom loadtime	windows10-64-shippable-qr	fission warm webrender	268.57 -> 300.22	Before/After
10%	fandom loadtime	windows10-64-shippable-qr	fission warm webrender	268.30 -> 295.73	Before/After

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)	Performance Profiles
3%	outlook LastVisualChange	linux1804-64-shippable-qr	fission warm webrender	2,220.92 -> 2,163.59	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.

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Comment 1

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

Set release status flags based on info from the regressing bug 1856545

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

loadtime itself isn't really a good metric to track page load progress. It doesn't tell anything about what is being shown to the user.
LastVisualChange on the other hand is visual metric.
So, I think I'm closing this as wontfix.

(I'm in process of landing various scheduling changes, so I expect some fluctuation in various metrics)