Closed Bug 1734558 Opened 3 months ago Closed 3 months ago

36 - 3.64% google-slides dcf / google-slides PerceptualSpeedIndex + 12 more (Android, Linux, OSX, Windows) regression on Wed September 29 2021

Categories

(Core :: Layout, defect)

Firefox 94
defect

Tracking

()

RESOLVED WONTFIX
Fission Milestone MVP
Tracking Status
firefox-esr78 --- unaffected
firefox-esr91 --- unaffected
firefox92 --- unaffected
firefox93 --- unaffected
firefox94 --- wontfix
firefox95 --- wontfix

People

(Reporter: alexandrui, Unassigned)

References

(Regression)

Details

(Keywords: perf, perf-alert, regression)

Perfherder has detected a browsertime performance regression from push e5a8c52f0f187ba8c5e70b060b4b19a39d7f193b. 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)
36% google-slides dcf linux1804-64-shippable-qr cold webrender 1,085.29 -> 1,476.00
36% google-slides dcf linux1804-64-shippable-qr cold fission webrender 1,070.56 -> 1,451.21
21% youtube dcf linux1804-64-shippable-qr warm webrender 968.10 -> 1,171.38
15% netflix dcf linux1804-64-shippable-qr warm webrender 408.02 -> 470.88
11% youtube ContentfulSpeedIndex linux1804-64-shippable-qr cold webrender 1,270.67 -> 1,413.00
11% youtube ContentfulSpeedIndex linux1804-64-shippable-qr warm webrender 780.67 -> 866.42
10% web-de dcf android-hw-g5-7-0-arm7-shippable-qr warm webrender 732.29 -> 804.75
6% google-docs SpeedIndex linux1804-64-shippable-qr cold webrender 1,796.88 -> 1,910.58
6% youtube ContentfulSpeedIndex macosx1015-64-shippable-qr cold webrender 1,475.79 -> 1,568.33
6% google-docs SpeedIndex linux1804-64-shippable-qr cold webrender 1,790.92 -> 1,900.33
4% google-docs SpeedIndex macosx1014-64-shippable-qr cold webrender 2,067.58 -> 2,158.92
4% youtube ContentfulSpeedIndex windows10-64-shippable-qr cold webrender 1,252.50 -> 1,305.83
4% youtube loadtime linux1804-64-shippable-qr warm webrender 1,235.67 -> 1,285.62
4% google-slides PerceptualSpeedIndex linux1804-64-shippable-qr cold webrender 1,018.96 -> 1,056.08

Improvements:

Ratio Test Platform Options Absolute values (old vs new)
25% google-docs-canvas LastVisualChange windows10-64-shippable-qr cold webrender 1,789.67 -> 1,339.92
20% google-docs-canvas LastVisualChange linux1804-64-shippable-qr cold webrender 1,800.00 -> 1,433.33
9% yahoo-mail ContentfulSpeedIndex macosx1014-64-shippable-qr fission warm webrender 537.12 -> 486.42
9% google-docs-canvas PerceptualSpeedIndex windows10-64-shippable-qr cold webrender 1,049.08 -> 952.67
7% google-docs-canvas LastVisualChange macosx1015-64-shippable-qr cold webrender 1,705.00 -> 1,580.00
... ... ... ... ...
4% google-docs-canvas SpeedIndex linux1804-64-shippable-qr cold webrender 1,071.42 -> 1,032.83

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.

Flags: needinfo?(dholbert)

Randell, do you think Daniel's "Don't tick during the process-switch period" fix (bug 1712123) could be responsible for these regressions? Daniel's patch landed on September 29. On the same day, Nika landed her bfcache process switch fix for bug 1731792, which was blamed for similar Google Slides regressions in bug 1734118.

Fission Milestone: --- → ?
Flags: needinfo?(rjesup)
See Also: → 1734118
Version: Firefox 95 → Firefox 94

I would bet cpeterson's theory (that this is actually fallout from bug 1712123) is correct.

But I'd also be happy to have my bug 1712123 patch backed out, to test the theory of whether it caused this regression. Nothing will break if my patch is backed out; it's just a minor tweak to disable an eager "try-to-paint-content-one-frame-sooner" behavior, during pageload.

Flags: needinfo?(dholbert)

Randell thinks we can accept these performance results and resolve this bug as wontfix. Some sites are faster, some are slower. He said the YouTube regressions are a little concerning, but he looked at test videos and the issue appears to be slower text loading, not affecting video loading.

Status: NEW → RESOLVED
Closed: 3 months ago
Flags: needinfo?(rjesup)
Resolution: --- → WONTFIX
Fission Milestone: ? → MVP
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