2046376 - 21.83% perf_reftest some-descendants-1.html (Linux) regression on Wed June 3 2026

Status: ASSIGNED

(Firefox Build System :: Toolchains, defect)

Description

[Treeherder Bug Filer]

Perfherder has detected a talos performance regression from push 7ffb408bfa80dc47e904cb74f918181502217b2a. 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]
22%	perf_reftest some-descendants-1.html (doc)	linux2404-64-shippable	e10s fission stylo webrender-sw	4.98 ms -> 6.07 ms

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 50754 (See documentation link for details).
• Profiling jobs: Trigger jobs from Treeherder job view or request them from [e-mail].

Comment 1

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

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

Comment 2

[Mike Hommey [:glandium]]

Attachment: Bug 2046376 - Upgrade smallvec to 1.15.2.