1556361 - 4.58% startup_about_home_paint (windows10-64-shippable) regression on push 07bb612a30b0c2f268a0ffcb50457315de37684e (Thu May 30 2019)

Status: RESOLVED WONTFIX

(Firefox :: New Tab Page, defect)

Description

[Ionuț Goldan [:igoldan]]

Talos has detected a Firefox performance regression from push:

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=ce21500c025e1435eb0dc2bdf168674d38a11b1f&tochange=07bb612a30b0c2f268a0ffcb50457315de37684e

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

Regressions:

5% startup_about_home_paint windows10-64-shippable opt e10s stylo 645.83 -> 675.42

You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=21186

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

[Ed Lee :Mardak]

Yes, we expected some change given that the page being tested is a different page with bug 1555390 loading the simple prerendered version of the page. We measured performance impact ahead of time and saw it was minimal for most platforms, and the version of the page currently tested matches the behavior that most users would see in 69+ which we have done screen recording tests and found parity with the old behavior for time to settle.

To be clear, this talos test is still desired and is now measuring something more representative of user's experience.