1522814 - 12.91 - 26.73% tp5o_scroll / tscrollx (linux64-qr, windows10-64-qr) regression on push bde038bd29375b06804a4a6a899779a63b852be0 (Wed Jan 23 2019)

Status: VERIFIED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Ionuț Goldan [:igoldan]]

Talos has detected a Firefox performance regression from push:

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=221f90b839ec18b16a58bd24f7827f4c51dfca48&tochange=bde038bd29375b06804a4a6a899779a63b852be0

As author of one of the patches included in that push, we need your help to address this regression.

Regressions:

27% tp5o_scroll linux64-qr opt e10s stylo 2.82 -> 3.57
21% tscrollx linux64-qr opt e10s stylo 1.89 -> 2.28
18% tp5o_scroll windows10-64-qr opt e10s stylo 1.96 -> 2.32
13% tscrollx windows10-64-qr opt e10s stylo 1.02 -> 1.15

You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=18846

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

[Glenn Watson [:gw]]

Wow, this is very surprising - I would have expected this to be a performance win in scrolling tests. I'll investigate these first thing Monday morning, thanks for the alert!

Comment 2

[Glenn Watson [:gw]]

This is addressed by the patch in https://bugzilla.mozilla.org/show_bug.cgi?id=1523210.

The try run [1] looks to restore those talos numbers to what they were previously, if I'm comparing correctly.

[1] https://treeherder.mozilla.org/#/jobs?repo=try&revision=b665cea36b03cbe9979953c169df2904b5a6cd4a&selectedJob=224375597

Comment 3

[Glenn Watson [:gw]]

Does this seem resolved and ready to close now?

Comment 4

[Ionuț Goldan [:igoldan]]

(In reply to Glenn Watson [:gw] from comment #3)

Does this seem resolved and ready to close now?

Yes, and I can confirm it with results:

== Change summary for alert #18974 (as of Mon, 28 Jan 2019 01:06:21 GMT) ==

Improvements:

19% tp5o_scroll linux64-qr opt e10s stylo 3.55 -> 2.88
16% tscrollx linux64-qr opt e10s stylo 2.29 -> 1.92
13% tp5o_scroll windows10-64-qr opt e10s stylo 2.31 -> 2.01
10% tscrollx windows10-64-qr opt e10s stylo 1.14 -> 1.03

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=18974