2014122 - 493.96 - 2.04% tp5o_scroll / startup_about_home_paint_cached + 7 more (Linux) regression on Fri January 30 2026

Status: RESOLVED DUPLICATE of bug 2013682

(Firefox :: Theme, defect, P1)

Description

[Treeherder Bug Filer]

Perfherder has detected a talos performance regression from push 8d54cc2c66e9d90b6f297c017c6294c3c6b30edd. 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]
494%	tp5o_scroll (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	1.45 -> 8.63
426%	tp5o_scroll_paint_skip (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	0.61 -> 3.21
35%	tp5o_scroll (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender	2.15 -> 2.91
27%	tp5o_scroll_paint_skip (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender	1.11 -> 1.41
9%	twinopen ext+twinopen:twinopen.html (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	157.75 ms -> 171.47 ms
3%	tabpaint (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	56.48 -> 57.95
3%	tresize (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	19.66 ms -> 20.16 ms
3%	sessionrestore (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	802.64 -> 822.83
2%	startup_about_home_paint_cached (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	1,012.83 -> 1,033.50

Improvements	Test	Platform	Options	Absolute values [old vs new]
9%	pdfpaint visibility_expressions.pdf (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	270.15 ms -> 245.78 ms
8%	pdfpaint issue17871_top_right.pdf (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	235.36 ms -> 216.01 ms
8%	pdfpaint issue2391-1.pdf (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	230.48 ms -> 212.62 ms
8%	pdfpaint issue7115.pdf (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	223.83 ms -> 206.60 ms
7%	pdfpaint issue8125.pdf (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	227.04 ms -> 210.05 ms
...	...	...	...	...
6%	pdfpaint issue6387.pdf (doc)	linux1804-64-shippable-qr	e10s fission stylo webrender-sw	276.76 ms -> 259.98 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 48384 (See documentation link for details).
• Profiling jobs: Trigger jobs from Treeherder job view or request them from [e-mail].

Comment 1

[Emilio Cobos Álvarez [:emilio]]

This is basically bug 2013682.

Comment 2

[BugBot [:suhaib / :marco]]

Set release status flags based on info from the regressing bug 2005854

Comment 3

[BugBot [:suhaib / :marco]]

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

:emilio, since you are the author of the regressor, bug 2005854, 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 4

[Emilio Cobos Álvarez [:emilio]]

There's activity in the dependent bug (bug 2013682).

Comment 5

[BugBot [:suhaib / :marco]]

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

:emilio, since you are the author of the regressor, bug 2005854, 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 6

[Emilio Cobos Álvarez [:emilio]]

See above.

Comment 7

[Pascal Chevrel (relman team) -> :pascalc]

Backed out from beta in bug 2005854

Comment 8

[BugBot [:suhaib / :marco]]

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

:emilio, since you are the author of the regressor, bug 2005854, 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 9

[Emilio Cobos Álvarez [:emilio]]

Sigh, see dependencies

Comment 10

[BugBot [:suhaib / :marco]]

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

:emilio, since you are the author of the regressor, bug 2005854, 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 11

[Emilio Cobos Álvarez [:emilio]]

Again, progress is happening in bug 2013682.

Comment 12

[Donal Meehan [:dmeehan]]

:emilio, it looks like this could be resolved now that Bug 2013682 has landed?
The pref alerts have returned to their previous values, as far as I can tell. Unless you were planning anything else here?

Comment 13

[Emilio Cobos Álvarez [:emilio]]

Yes