1579403 - 13.87% sccache hit rate (linux32) regression on push 55715c676a88225379c56c94de4d153d8795c346 (Tue September 3 2019)

Status: RESOLVED INVALID

(Core :: JavaScript: WebAssembly, defect)

Description

[Marian Raiciof [:marauder]]

We have detected a build metrics regression from push:

https://hg.mozilla.org/integration/autoland/pushloghtml?changeset=55715c676a88225379c56c94de4d153d8795c346

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

Regressions:

14% sccache hit rate linux32 debug 1.00 -> 0.86

You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=22948

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 jobs in a pushlog format.

To learn more about the regressing test(s), please see: https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Automated_Performance_Testing_and_Sheriffing/Build_Metrics

*** Please let us know your plans within 3 business days, or the offending patch(es) will be backed out! ***

Comment 1

[Benjamin Bouvier [:bbouvier] (inactive)]

Any chance this could have been bug 1575198 instead? The commit mentioned here doesn't involve anything related to the build system, and it seems quite unlikely it was the cause of a build regression.

Comment 2

[Marian Raiciof [:marauder]]

Hi Benjamin, I am not sure, i'll wait for Mike's opinion.

Mike - what do you think about https://bugzilla.mozilla.org/show_bug.cgi?id=1579403#c1 ?

Thanks!

Comment 3

[Mike Hommey [:glandium]]

Something, whatever that was, landed with header changes that required a lot of builds or something along those lines. Hit rate recovered after, this is business as usual. Sccache hit rate regressions should only be filed as such if the hit rates stays low for a long time.