1744735 - 56.59 - 2.96% imgur ContentfulSpeedIndex / youtube LastVisualChange + 10 more (Android, Linux, OSX, Windows) regression on Thu December 2 2021

Status: RESOLVED WONTFIX

(Testing :: Raptor, defect)

Description

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

Perfherder has detected a browsertime performance regression from push e0c7e7f0f1de0b32206f00a29941a6b746bad024. 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)
57%	imgur ContentfulSpeedIndex	macosx1015-64-shippable-qr	warm webrender	247.25 -> 387.17
13%	linkedin fnbpaint	macosx1015-64-shippable-qr	warm webrender	321.75 -> 364.88
10%	youtube fcp	linux1804-64-shippable-qr	warm webrender	299.12 -> 329.25
9%	youtube fnbpaint	linux1804-64-shippable-qr	warm webrender	309.58 -> 337.29
7%	youtube fnbpaint	windows10-64-shippable-qr	warm webrender	287.19 -> 307.96
7%	linkedin SpeedIndex	macosx1015-64-shippable-qr	warm webrender	775.79 -> 827.75
6%	linkedin PerceptualSpeedIndex	macosx1015-64-shippable-qr	warm webrender	861.29 -> 914.50
5%	dailymail loadtime	android-hw-g5-7-0-arm7-shippable-qr	warm webrender	2,381.92 -> 2,508.29
5%	dailymail LastVisualChange	android-hw-g5-7-0-arm7-shippable-qr	warm webrender	2,413.33 -> 2,537.58
5%	youtube fnbpaint	windows10-64-shippable-qr	warm webrender	289.62 -> 304.46
5%	youtube fcp	windows10-64-shippable-qr	warm webrender	282.02 -> 294.96
3%	youtube LastVisualChange	linux1804-64-shippable-qr	warm webrender	2,868.33 -> 2,953.33

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)
86%	tumblr LastVisualChange	macosx1015-64-shippable-qr	warm webrender	6,200.00 -> 873.33
86%	tumblr LastVisualChange	windows10-64-shippable-qr	warm webrender	5,944.33 -> 838.75
85%	tumblr LastVisualChange	linux1804-64-shippable-qr	warm webrender	5,990.00 -> 893.33
76%	tumblr LastVisualChange	windows10-64-shippable-qr	cold webrender	7,050.25 -> 1,686.25
76%	tumblr LastVisualChange	windows10-64-shippable-qr	cold webrender	7,038.00 -> 1,719.83
...	...	...	...	...
4%	tumblr ContentfulSpeedIndex	linux1804-64-shippable-qr	cold webrender	1,029.08 -> 990.25

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.