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

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.

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.

ok, closing