Talos has detected a Firefox performance regression from push:

https://hg.mozilla.org/integration/autoland/pushloghtml?changeset=a5710687f9b44562f9ee54907ce81beb386da41b

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

Regressions:

9% tp5n main_startup_fileio windows10-64-shippable-qr opt e10s stylo 911,705.67 -> 993,113.67

You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=22605

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/TestEngineering/Performance/Talos

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

My understanding is that this is expected and just an artifact of the fact that the fileio tests run in VMs rather than on hardware. Now that we're running QR VM tests on non-GPU VMs, we'll get WARP, which means loading an extra DLL on startup. But we generally won't actually be doing that in the wild.

So let's tentatively assume this should just be a baseline update, but let Jeff confirm when he gets back from PTO.

As for Comment 1 marking this as won't fix