1717204 - 6.96 - 6.45% wasm-godot-optimizing / wasm-godot-optimizing (Linux) regression on Wed June 16 2021

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect, P1)

Description

[Florin Strugariu [:Bebe]]

Perfherder has detected a browsertime performance regression from push dba01ea36c18a636ccdf5d58644de41003ef38ff. As author of one of the patches included in that push, we need your help to address this regression.

Regressions:

Ratio	Suite	Test	Platform	Options	Absolute values (old vs new)
7%	wasm-godot-optimizing		linux1804-64-shippable-qr	webrender	1,317.18 -> 1,408.90
6%	wasm-godot-optimizing		linux1804-64-shippable-qr	webrender	1,320.53 -> 1,405.75

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.

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 1715562

Comment 2

[Jon Coppeard (:jonco)]

Investigating.

Comment 3

[Jon Coppeard (:jonco)]

Attachment: Bug 1717204 - Increase the number of threads used by the XPCOM thread pool to match the number of cores r?bas

Currently the XPCOM thead pool creates one less thread than the number of
cores. The JS helper thread pool creates an equal number.

I tested increasing the number of threads to match the number of cores and
found it resolved this regression.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/92d402a0839b
Increase the number of threads used by the XPCOM thread pool to match the number of cores r=bas

Comment 5

[Dorel Luca [:dluca]]

https://hg.mozilla.org/mozilla-central/rev/92d402a0839b

Comment 6

[Florin Strugariu [:Bebe]]

== Change summary for alert #30484 (as of Mon, 28 Jun 2021 17:20:37 GMT) ==

Improvements:

Ratio	Suite	Test	Platform	Options	Absolute values (old vs new)
6%	wasm-godot-optimizing		linux1804-64-shippable-qr	webrender	1,417.52 -> 1,328.29
6%	wasm-godot-optimizing		linux1804-64-shippable-qr	webrender	1,419.35 -> 1,333.61

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=30484