1379613 - 19.34% sessionrestore_many_windows (windows10-64) regression on push bb672269322d4b764ec0c1b8fad13b57f3939b5b (Fri Jul 7 2017)

Status: RESOLVED WONTFIX

(Firefox :: Theme, defect)

Description

[Ionuț Goldan [:igoldan]]

Talos has detected a Firefox performance regression from push:

https://hg.mozilla.org/integration/autoland/pushloghtml?changeset=bb672269322d4b764ec0c1b8fad13b57f3939b5b

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

Regressions:

 19%  sessionrestore_many_windows windows10-64 opt e10s     3,676.91 -> 4,387.92


You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=7761

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/Buildbot/Talos/Tests

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

Comment 1

[Ionuț Goldan [:igoldan]]

::dao This is a Windows 10-only issue, an only affects its OPT builds; the related PGO doesn't appear to be affected at all. This surely requires at least an investigation, if not a fix.

Comment 2

[Dão Gottwald [:dao]]

I can't explain this and don't know how we could undo the regression. Anyway, this is the reversal of bug 1196266 comment 67 and as such I think it's wontfix.