1501606 - 4.95 - 5.69% tp5o_scroll (linux64-qr, windows10-64-qr) regression on push bd15c0cbc18ab4fc6dcac68c8be86a88e1ee7e76 (Tue Oct 23 2018)

Status: RESOLVED INVALID

(Core :: Graphics: WebRender, defect, P3)

Description

[Ionuț Goldan [:igoldan]]

Talos has detected a Firefox performance regression from push:

https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?changeset=bd15c0cbc18ab4fc6dcac68c8be86a88e1ee7e76

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

Regressions:

  6%  tp5o_scroll linux64-qr opt e10s stylo          3.84 -> 4.06
  5%  tp5o_scroll windows10-64-qr opt e10s stylo     2.66 -> 2.79


You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=17066

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

[Ionuț Goldan [:igoldan]]

I'm afraid I don't have any Gecko profiles for this regression.
I attempted to collect them here [1], but without luck.

[1] https://treeherder.mozilla.org/#/jobs?repo=mozilla-inbound&group_state=expanded&searchStr=linux%2Cx64%2Cquantumrender%2Copt%2Ctalos%2Cperformance%2Ctests%2Cwith%2Ce10s%2Ctest-linux64-qr%2Fopt-talos-g1-e10s%2Ct-e10s%28g1-p%29&tochange=bd15c0cbc18ab4fc6dcac68c8be86a88e1ee7e76&fromchange=a0fac96b947ef3dbcd50106e66d14b8ff4b5a7fa

Comment 2

[Sotaro Ikeda [:sotaro]]

Hmm, it is unexpected regression. Bug 1500821 just skip calling RecordFrame() when it should not. It is necessary change to get corect Talos measures.

Comment 3

[Sotaro Ikeda [:sotaro]]

I think we should just accept this for now.

Comment 4

[Sotaro Ikeda [:sotaro]]

Bug 1500821 fixes frame time recording like LayerManagerComposite. But it regress the recording than before Bug 1500821.

The frame time recording is used for talos scroll testing. Then the change was observed as a regression. But it just fixed the recording.
  https://dxr.mozilla.org/mozilla-central/source/testing/talos/talos/pageloader/chrome/tscroll.js#238