1868537 - 57.92 - 56.59% damp simple.netmonitor.requestsFinished.DAMP / damp simple.netmonitor.requestsFinished.DAMP (Windows) regression on Tue November 21 2023

Status: RESOLVED WONTFIX

(DevTools :: Framework, defect)

Description

[Hubert Boma Manilla (:bomsy)]

Perfherder has detected a devtools performance regression from push 1ff1d467cb8d49467127613245f448026cd7df9e. 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)
58%	damp simple.netmonitor.requestsFinished.DAMP	windows10-64-shippable-qr	e10s fission stylo webrender-sw	114.71 -> 181.15
57%	damp simple.netmonitor.requestsFinished.DAMP	windows10-64-shippable-qr	e10s fission stylo webrender	115.93 -> 181.54

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 patch(es) may 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 1651522

Comment 2

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

The bug is marked as tracked for firefox122 (nightly). We have limited time to fix this, the soft freeze is in 7 days. However, the bug still isn't assigned.

:Honza, could you please find an assignee for this tracked bug? Given that it is a regression and we know the cause, we could also simply backout the regressor. If you disagree with the tracking decision, please talk with the release managers.

For more information, please visit BugBot documentation.

Comment 3

[Jan Honza Odvarko [:Honza] (always need-info? me)]

Sorry for the dela (we had a team workweek last week)

Alex, please take a look, thank you!

Honza

Comment 4

[Alexandre Poirot [:ochameau]]

I could reproduce locally, but can't see anything really obvious.
Here is a profile comparison for the regressed subtest:
https://share.firefox.dev/3RiJN8M
This is a bit surprising that the Service Worker patch has an impact as it is still behind the service worker window-less pref, and should only start doing things when the debugger is opened.

The only things I've been able to catch on the profiler is updateDomainSessionDataForServiceWorkers, which may take 10% of the subtest.
This code should hopefully go away when we stop filtering service worker by domain.

Given that the regression only impact blank document debugging, closing as WONTFIX.
This may have regressed the startup time of netmonitor, but not enough to be visible against a non-blank document.
We could probably have a better impact by chasing other low hanging fruits.