Talos has detected a Firefox performance regression from push: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?changeset=81ef11104ebb7871c6efe1794a40d4505a80c8dd As author of one of the patches included in that push, we need your help to address this regression. Regressions: 3% kraken linux64 opt e10s stylo 898.79 -> 924.30 You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=12588 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

:jandem, the changes you made in bug 1448887 seem to have caused a slight regression in kraken on linux/windows. here are the subtests: https://treeherder.mozilla.org/perf.html#/comparesubtest?originalProject=mozilla-inbound&originalRevision=ac22879df707357a8169c81d20b737ed81251205&newProject=mozilla-inbound&newRevision=81ef11104ebb7871c6efe1794a40d4505a80c8dd&originalSignature=123a08fb5b7095bf46b82502d49f9b71e16aa3ad&newSignature=123a08fb5b7095bf46b82502d49f9b71e16aa3ad&framework=1 Can you look into this and determine if this is something expected, should be fixed, or should be backed out?

https://bugzilla.mozilla.org/show_bug.cgi?id=1448887#c10 makes it sound like they were expected.

(In reply to Ryan VanderMeulen [:RyanVM] from comment #2) > https://bugzilla.mozilla.org/show_bug.cgi?id=1448887#c10 makes it sound like > they were expected. Yeah it's unfortunate but bug 1448887 fixes a crash (bug 1446907), removes some really complicated (and platform-specific) code, and should improve performance in some other cases (workers) so we decided landing that was the right trade-off.

Resolving as wontfix as it was an expected change with trade-offs weighed and accepted.