2047135 - 6.4 - 5.61% jetstream3 cdjs-Average + 3 more (OSX) regression on Tue June 9 2026

Status: RESOLVED DUPLICATE of bug 2046376

(Firefox Build System :: Toolchains, defect)

Description

[Treeherder Bug Filer]

Perfherder has detected a browsertime performance regression from push f310e997ae26a071d423bd408830fd8934027242. 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.

Regression	Test	Platform	Options	Absolute values [old vs new]
6%	jetstream3 cdjs-Average (doc)	macosx1470-64-shippable	fission webrender	80.76 -> 85.93
6%	jetstream3 cdjs-Worst (doc)	macosx1470-64-shippable	fission webrender	83.59 -> 88.78
6%	jetstream3 cdjs-Average (doc)	macosx1500-aarch64-shippable	fission webrender	23.51 -> 24.86
6%	jetstream3 cdjs-Geometric (doc)	macosx1470-64-shippable	fission webrender	59.45 -> 56.11

Support & Actionable Steps

For questions, please contact [e-mail]. You can also find help on Slack (#perf-help) or Matrix (#perftest).

Action guide details:

• See the guide to handling regression bugs for investigation steps.
• Review the alert summary for affected tests, graphs, and comparisons.
• Check the PerfCompare results.
• Tests on Try: Run all tests using ./mach try perf --alert 50799 (See documentation link for details).
• Profiling jobs: Trigger jobs from Treeherder job view or request them from [e-mail].

Comment 1

[BugBot [:suhaib / :marco]]

Set release status flags based on info from the regressing bug 2002120

Comment 2

[Mike Hommey [:glandium]]

Considering webrender is using smallvec, it's very possible it's the same underlying thing as bug 2046376. Let's see how things go after the fix for that one lands.

Comment 4

[Emilio Cobos Álvarez [:emilio]]

Huh. But isn't Jetstream supposed to be a JS benchmark? If webrender affects it it seems bad...