1847781 - 7.57% espn LastVisualChange (OSX) regression on Mon July 24 2023

Status: RESOLVED WONTFIX

(Core :: Security, defect)

Description

[Alex Finder]

Perfherder has detected a browsertime performance regression from push b07ba27a26e00e09eb7e6cc04d9c567ed23756eb. 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)	Performance Profiles
8%	espn LastVisualChange	macosx1015-64-shippable-qr	cold fission webrender	2,141.97 -> 2,304.10	Before/After

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) may be backed out in accordance with our regression policy.

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Comment 1

[Alex Finder]

Hi Ren! Please leave a :needinfo if you think 1844492 is the actual culprit for the defect, instead of 1842971, or if you have any other questions about this defect.

Comment 2

[BugBot [:suhaib / :marco]]

Set release status flags based on info from the regressing bug 1842971

Comment 3

[Emilio Cobos Álvarez [:emilio]]

How sure are we about the regressing bugs? It feels fairly unlikely that either of those actually regress perf.

Comment 4

[Alex Finder]

(In reply to Emilio Cobos Álvarez (:emilio) from comment #3)

How sure are we about the regressing bugs? It feels fairly unlikely that either of those actually regress perf.

Retriggered before the identified culprit, and it seems to have made the graph a bit noisy around that revision. Retriggered before b16351df250c572a14efa126f7702fe104ac9fd7 as well to check if it might be an infra. Will recheck later in the day.

Comment 5

[Alex Finder]

As visible in the following graph, where we can see both the culprit revision (b07ba27a26e00e09eb7e6cc04d9c567ed23756eb) and the revision triggered before that (b16351df250c572a14efa126f7702fe104ac9fd7), it looks like the graph's trend change was caused by an infra change. I'll close the defect as WON'T FIX and tag the alert as "infra". Thanks for the help Emilio!