1422685 - 9.46 - 14.04% tps (linux64, osx-10-10, windows10-64, windows7-32) regression on push 8994162ee112a8c0a0b33f3404f04ebd9fad1285 (Sat Dec 2 2017)

Status: RESOLVED FIXED

(Firefox :: Untriaged, defect)

Description

[Ionuț Goldan [:igoldan]]

Talos has detected a Firefox performance regression from push:

https://hg.mozilla.org/integration/autoland/pushloghtml?changeset=8994162ee112a8c0a0b33f3404f04ebd9fad1285

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

Regressions:

 14%  tps linux64 opt e10s     28.07 -> 32.01
 13%  tps windows7-32 opt e10s 21.77 -> 24.70
 13%  tps windows10-64 opt e10s22.87 -> 25.79
 12%  tps linux64 pgo e10s     26.45 -> 29.67
 11%  tps windows7-32 pgo e10s 18.94 -> 21.02
  9%  tps osx-10-10 opt e10s   21.59 -> 23.64
  9%  tps windows10-64 pgo e10s21.87 -> 23.94


You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=10845

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]]

:mconley Should we accept these regressions or is there something we can do about them?

Comment 2

[Mike Conley (:mconley) (:⚙️)]

Thanks, igoldan - looking...

Comment 3

[Mike Conley (:mconley) (:⚙️)]

Bug 1397426 was backed out.

I'll try to figure out what this regression is all about before re-landing.

Comment 4

[Mike Conley (:mconley) (:⚙️)]

I think I figured out the regression - the init() function in the async tab switcher was eating time initializing the rendering state for each tab. My new patches in bug 1397426 do this lazily, and the regression appears to be gone now.

\o/ Hooray for Talos catching a regression!

Comment 5

[Ionuț Goldan [:igoldan]]

Awesome!