Raptor has detected a Firefox performance regression from push:

https://hg.mozilla.org/integration/autoland/pushloghtml?changeset=868a55980ae8e0f6bda936e9a5c0cbb2311a5717

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

Regressions:

2% raptor-tp6-slides-firefox fcp windows7-32-shippable opt 765.19 -> 781.21

You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=23986

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 Raptor jobs in a pushlog format.

To learn more about the regressing test(s) or reproducing them, please see: https://wiki.mozilla.org/TestEngineering/Performance/Raptor

*** 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/TestEngineering/Performance/Talos/RegressionBugsHandling

We probably need to accept this regression. It is surprising it made a change however. We were already snapping the rounded clip rects during scene building, so this would just make the rects slightly smaller or slightly bigger depending on the scenario. Maybe it subtly impacted picture caching or something behaviour.

Andrew, this is 3 months old. Any intention on fixing this?

The original backout in bug 1604535 fixed this. We restricted disabling OMTP to a more targeted population that was more clearly impacted by its limitations, and did not get its benefits; CI was not included in this group due to how many cores are available.