1559332 - 3.71% tp5o_scroll (windows10-64-shippable) regression on push b9e525d8b1aa6659c6cc95956dafae65c28daa62 (Mon June 3 2019)

Status: RESOLVED WONTFIX

(Core :: Graphics, defect)

Description

[Ionuț Goldan [:igoldan]]

Talos has detected a Firefox performance regression from push:

https://hg.mozilla.org/releases/mozilla-beta/pushloghtml?fromchange=fa85a070d83364097722aeb109b110eba62b51f8&tochange=b9e525d8b1aa6659c6cc95956dafae65c28daa62

We need your help to address this regression.

Regressions:

4% tp5o_scroll windows10-64-shippable opt e10s stylo 1.22 -> 1.27

You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=21342

On the page above you can see an alert for each affected platform as well as a link to a graph showing the history of scores for this test. There is also a link to a treeherder page showing the Talos jobs in a pushlog format.

To learn more about the regressing test(s), please see: https://wiki.mozilla.org/Performance_sheriffing/Talos/Tests

For information on reproducing and debugging the regression, either on try or locally, see: https://wiki.mozilla.org/Performance_sheriffing/Talos/Running

*** Please let us know your plans within 3 business days, or the offending patch(es) will be backed out! ***

Our wiki page outlines the common responses and expectations: https://wiki.mozilla.org/Performance_sheriffing/Talos/RegressionBugsHandling

Comment 1

[Ionuț Goldan [:igoldan]]

Somehow, I'm not able to bisect via Try the entire patch. So I need your help on this.
Out of the 4 suspects patches which I've managed to narrow down, which one is the likely cause?

Comment 2

[Ionuț Goldan [:igoldan]]

Scrolling relates to page navigation, which seems related to Core :: Document Navigation.
Would this further narrow the list to just bug 1555688 & bug 1554217?

Comment 3

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

Should be from bug 1555956. Bug 1555688 only modifies a test file, bug 1554217 had landed before and got backed out but there is no talos regression for that push. Also bug 1555956 is about disabling a Windows feature (direct3d11) and the regression is on Windows.

Comment 4

[Ionuț Goldan [:igoldan]]

(In reply to Sebastian Hengst [:aryx] (needinfo on intermittent or backout) from comment #3)

Should be from bug 1555956.

:kats can you take a look over this issue & confirm it?

Comment 5

[Haik Aftandilian [:haik]]

(In reply to Sebastian Hengst [:aryx] (needinfo on intermittent or backout) from comment #3)

Should be from bug 1555956. Bug 1555688 only modifies a test file, bug 1554217 had landed before and got backed out but there is no talos regression for that push. Also bug 1555956 is about disabling a Windows feature (direct3d11) and the regression is on Windows.

And bug 1555168 is Mac-specific.

Comment 6

[Kartikaya Gupta (email:[e-mail])]

Yeah it's quite plausible that the regression is from disabling double-buffering. But double buffering was only recently enabled in bug 1547775, and the feature quality is not good enough to let it ride the trains, so this perf regression is a wontfix.