Talos has detected a Firefox performance regression from push:

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=9c8509157a9ffb46ba1a093354cd31255ab6f868&tochange=72fc109fe0f203a360003b1f4f7a775ab161cfe4

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

Regressions:

7% tp5o responsiveness linux64-shippable opt e10s stylo 1.39 -> 1.48
4% tp5o responsiveness linux64-shippable-qr opt e10s stylo 1.77 -> 1.84
2% tp5o_webext responsiveness linux64-shippable-qr opt e10s stylo 2.11 -> 2.16

You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=21239

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

Unfortunately, I cannot provide any Gecko profiles, as they seem to be broken.

This should be fixed by the partial backout of bug 1167452. But I'm going to have to look at it in order to re-land. I was hoping for this to have the opposite effect. :-(

(In reply to Steve Fink [:sfink] [:s:] from comment #2)
The changes blamed have been backed out but this doesn't seem to have fixed the regression (at least from what I could see). igoldan where does that leave us with this bug?

:igoldan is on pto until 22-july, :bebe can you help out here?

I am hoping https://bugzilla.mozilla.org/show_bug.cgi?id=1553332 will fix this.

There was a improvement in the area of the backout but it was caused by the previous commit and it was way less than the regression.

== Change summary for alert #21722 (as of Wed, 03 Jul 2019 09:18:49 GMT) ==

Improvements:

2% tp5o_webext responsiveness linux64-shippable-qr opt e10s stylo 2.16 -> 2.12
2% tp5o_webext responsiveness linux64-shippable-qr opt e10s stylo 2.16 -> 2.13

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=21722

Let's wait for progress on bug 1553332 and see if we can get a fix

(In reply to Jon Coppeard (:jonco) from comment #3)

(In reply to Steve Fink [:sfink] [:s:] from comment #2)
The changes blamed have been backed out but this doesn't seem to have fixed the regression (at least from what I could see). igoldan where does that leave us with this bug?

Removing ni? from myself as Florin provided the response.

The relevant patches are now all backed out. The final one was:

changeset: https://hg.mozilla.org/mozilla-central/rev/4ad75b878827
user: Steve Fink
date: Wed Jul 24 14:29:22 2019 -0700
summary: Backed out changeset 617df479fac1 (bug 1167452)

Marking this as resolved. Note that I still want to make the change that triggered this. I will do so in a new bug.