1877408 - 27.61 - 6.79% twitch fcp / twitch loadtime + 5 more (Linux, Windows) regression on Mon January 22 2024

Status: RESOLVED WONTFIX

(Core :: DOM: Core & HTML, defect)

Description

[Acasandrei Beatrice (needinfo me)]

Perfherder has detected a browsertime performance regression from push 859c538033a5d0fc06c7012735e981cdb099d476. 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
28%	twitch fcp	linux1804-64-shippable-qr	fission warm webrender	170.52 -> 217.60	Before/After
27%	reddit-billgates-post-2.top LastVisualChange	linux1804-64-shippable-qr	cold fission webrender	289.22 -> 366.72	Before/After
18%	reddit-billgates-post-2.top FirstVisualChange	windows10-64-shippable-qr	cold fission webrender	76.33 -> 90.19	Before/After
16%	reddit-billgates-post-2.top SpeedIndex	windows10-64-shippable-qr	cold fission webrender	106.91 -> 123.87	Before/After
11%	reddit-billgates-post-2.top PerceptualSpeedIndex	windows10-64-shippable-qr	cold fission webrender	170.19 -> 188.56	Before/After
8%	reddit-billgates-post-2.top LastVisualChange	windows10-64-shippable-qr	cold fission webrender	359.00 -> 389.21	Before/After
7%	twitch loadtime	linux1804-64-shippable-qr	fission warm webrender	846.78 -> 904.30	Before/After

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)	Performance Profiles
16%	expedia largestContentfulPaint	macosx1015-64-shippable-qr	fission warm webrender	71.79 -> 60.15	Before/After
13%	expedia largestContentfulPaint	macosx1015-64-shippable-qr	fission warm webrender	68.92 -> 59.74	Before/After
3%	youtube ContentfulSpeedIndex	linux1804-64-shippable-qr	fission warm webrender	1,138.55 -> 1,098.95	Before/After
3%	nytimes PerceptualSpeedIndex	linux1804-64-shippable-qr	fission warm webrender	405.28 -> 393.88	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 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.

You can run these tests on try with ./mach try perf --alert 41172

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 1871552

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

The patch in bug 1871552 was basically fixing the regression which occurred because of bug 1870477.
So the numbers, for example reddit-billgates-post-2.top , is just getting back to where it was.