Talos has detected a Firefox performance regression from push: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?changeset=120d17a176ffa033fe79632804755ae23940c336 As author of one of the patches included in that push, we need your help to address this regression. Regressions: 3% sessionrestore windows10-64 pgo e10s stylo 213.42 -> 219.83 3% sessionrestore windows7-32 pgo e10s stylo 230.83 -> 237.60 3% sessionrestore_no_auto_restore windows10-64 pgo e10s stylo276.00 -> 283.00 You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=13491 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

:kmag I beliew this is just a test harness update. We can mark this as WONTFIX unless you see something fishy.

It's mostly a harness change, but there's also the addition of an async call to create an empty directory if it doesn't exist. I can't see how that would cause a significant regression, though, unless we don't already have the directory in talos runs, and having the directory is what causes the regression. In that case, though, this isn't a regression we'd see for most users in the wild, since most users will already have the profile extensions directory.