1980583 - 11.86 - 3.27% damp jstracer.profiler-collection-performance.DAMP / damp jstracer.profiler-recording-performance.DAMP + 4 more (Linux, OSX, Windows) regression on Thu July 24 2025

Status: RESOLVED WONTFIX

(DevTools :: Debugger, defect)

Description

[Treeherder Bug Filer]

Perfherder has detected a devtools performance regression from push 0c7eeec56eab2c8953b1c6c85e767e0ea6f52355. 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)
12%	damp jstracer.profiler-collection-performance.DAMP	macosx1470-64-shippable	e10s fission stylo webrender	456.84 -> 511.00
10%	damp jstracer.profiler-collection-performance.DAMP	windows11-64-24h2-shippable	e10s fission stylo webrender	213.14 -> 234.82
8%	damp jstracer.profiler-collection-performance.DAMP	linux1804-64-shippable-qr	e10s fission stylo webrender	660.26 -> 712.05
6%	damp jstracer.profiler-recording-performance.DAMP	macosx1470-64-shippable	e10s fission stylo webrender	294.27 -> 312.18
6%	damp jstracer.profiler-recording-performance.DAMP	linux1804-64-shippable-qr	e10s fission stylo webrender	510.51 -> 539.21
3%	damp jstracer.profiler-recording-performance.DAMP	windows11-64-24h2-shippable	e10s fission stylo webrender	136.35 -> 140.81

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 46083

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 1933787

Comment 2

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

It has been over 7 days with no activity on this performance regression.

:alexical, since you are the author of the regressor, bug 1933787, which triggered this performance alert, could you please provide a progress update?

If this regression is something that fixes a bug, changes the baseline of the regression metrics, or otherwise will not be fixed, please consider closing it as WONTFIX. See this documentation for more information on how to handle regressions.

For additional information/help, please needinfo the performance sheriff who filed this alert (they can be found in comment #0), or reach out in #perftest, or #perfsheriffs on Element.

For more information, please visit BugBot documentation.

Comment 3

[Alex Thayer [:alexical] (she/her)]

Hey! Sorry for the delay here. I'm comfortable with this as-is. This adds significant functionality to the JS Execution Tracer and we're just seeing the cost of that additional functionality on the tracer itself.

Comment 4

[Julian Descottes [:jdescottes]]

Thanks for checking!