1465012 - 2.54 - 3.01% sessionrestore / sessionrestore_no_auto_restore (windows10-64, windows7-32) regression on push 120d17a176ffa033fe79632804755ae23940c336 (Mon May 28 2018)

Status: RESOLVED WONTFIX

(Testing :: Mochitest, defect)

Description

[Ionuț Goldan [:igoldan]]

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

Comment 1

[Ionuț Goldan [:igoldan]]

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

Comment 2

[Kris Maglione [:kmag]]

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.