1545735 - 2.03% sessionrestore (linux64-shippable-qr) regression on push df43e036b44d (Fri Apr 5 2019)

Status: RESOLVED WONTFIX

(Core :: Graphics: Layers, defect)

Description

[Ionuț Goldan [:igoldan]]

Talos has detected a Firefox performance regression from push:

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=75d1ab7e1346bdfc272bd07d6a8ff38a52691172&tochange=df43e036b44d681f77e9d2419a0f9d6bb0d5159c

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

Regressions:

2% sessionrestore linux64-shippable-qr opt e10s stylo 929.67 -> 948.58

You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=20518

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/Performance_sheriffing/Talos/Tests

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

Comment 1

[Aria Beingessner [:Gankra]]

I expect this will have to be considered an acceptable regression, as the fix in question was a necessary one for correctness. Although it is surprising that such a small change would show up so noticeably in the profiles. Will consult with other members of the gfx team.

Comment 2

[Dzmitry Malyshau [:kvark]]

The driver doesn't like our slightly more complex shader. It would be good to understand the particular things a driver cares about, but certainly not within this scope of this bug, and certainly at low priority (linux only, driver dependent). I agree the regression to be acceptable.

Comment 3

[Aria Beingessner [:Gankra]]

ok, closing