1766439 - 9.99 - 5.95% perf_reftest_singletons parent-basic-singleton.html / perf_reftest_singletons attr-selector-1.html + 1 more (Linux, Windows) regression on Thu April 21 2022

Status: RESOLVED WONTFIX

(Firefox Build System :: Toolchains, defect)

Description

[Andrej (:aglavic)]

Perfherder has detected a talos performance regression from push 5bebcdfc5dd864f94cf6af8e418fd3900995bc28. 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)
10%	perf_reftest_singletons parent-basic-singleton.html	windows10-64-shippable-qr	e10s fission stylo webrender	80.30 -> 88.32
7%	perf_reftest_singletons parent-basic-singleton.html	linux1804-64-shippable-qr	e10s fission stylo webrender	91.48 -> 97.48
6%	perf_reftest_singletons attr-selector-1.html	linux1804-64-shippable-qr	e10s fission stylo webrender	139.56 -> 147.87

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)
18%	perf_reftest_singletons id-getter-4.html	windows10-64-shippable-qr	e10s fission stylo webrender	394.74 -> 323.22
18%	perf_reftest_singletons id-getter-3.html	windows10-64-shippable-qr	e10s fission stylo webrender	394.74 -> 323.84
18%	perf_reftest_singletons id-getter-6.html	windows10-64-shippable-qr	e10s fission stylo webrender	394.63 -> 323.75
18%	perf_reftest_singletons id-getter-5.html	windows10-64-shippable-qr	e10s fission stylo webrender	394.94 -> 324.60
18%	perf_reftest_singletons id-getter-7.html	windows10-64-shippable-qr	e10s fission stylo webrender	394.35 -> 324.75
...	...	...	...	...
4%	tabswitch	linux1804-64-shippable-qr	e10s fission stylo webrender	7.23 -> 6.91

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 offending patch(es) will be backed out in accordance with our regression policy.

If you need the profiling jobs you can trigger them yourself from treeherder job view or ask a sheriff to do that for you.

For more information on performance sheriffing please see our FAQ.

Comment 1

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

Set release status flags based on info from the regressing bug 1758780

Comment 2

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

== Change summary for alert #33979 (as of Fri, 29 Apr 2022 02:39:03 GMT) ==

Regressions:

Ratio	Test	Platform	Options	Absolute values (old vs new)
3%	microsoft-support LastVisualChange	android-hw-g5-7-0-arm7-shippable-qr	warm webrender	2,616.38 -> 2,691.10

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=33979

Comment 3

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

Set release status flags based on info from the regressing bug 1758780

Comment 4

[Mike Hommey [:glandium]]

Can't tell about comment 2, but the ones in comment 0 seem to all be a regression in stylo with rustc 1.60. Emilio, do you want to look into this?

Comment 5

[Emilio Cobos Álvarez [:emilio]]

I took a look and while I can reproduce they aren't terribly concerning.

Sent a few selector-matching improvements that improve the generated code, but we're in micro-optimization-land at this point.

Comment 6

[Ryan VanderMeulen [:RyanVM]]

Doesn't look like the graphs changed much after the various deps landed. Was there more you wanted to try here still or should we close this out as a wontfix?

Comment 7

[Emilio Cobos Álvarez [:emilio]]

Yeah, I don't plan to look into it deeper atm.