1569202 - 15.93% build times (linux64-shippable) regression on push 914ff68da4e4f3e790472011ca53bf6ef457a240 (Fri July 19 2019)

Status: RESOLVED DUPLICATE of bug 1568152

(Firefox Build System :: General, defect)

Description

[Marian Raiciof [:marauder]]

We have detected a build metrics regression from push:

https://hg.mozilla.org/integration/autoland/pushloghtml?changeset=914ff68da4e4f3e790472011ca53bf6ef457a240

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

Regressions:

16% build times linux64-shippable opt nightly taskcluster-m5.4xlarge 3,909.18 -> 4,531.98

You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=21983

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

[Aria Beingessner [:Gankra]]

This looks like some kind of wild error by automation. A 16% build time regression is absolutely catastrophic and this patch barely does anything (no new imports, very small code changes).

Comment 2

[Lee Salzman [:lsalzman]]

This certainly seems like an error given that my patch is for the Windows code, and isn't changing enough to affect build times. There are a ton of other patches in the same window which have a much greater likelihood of affecting build times, to the point where I don't know why this patch got singled out at all.

See https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=5fceb8c496bfe98c1081d9ff8712e9107dd22767&tochange=dc32c9061a0a335dd582845703cd742c55be9c85
as per https://treeherder.mozilla.org/perf.html#/graphs?series=mozilla-central,1583096,1,2&series=mozilla-central,1954028,1,2&selected=mozilla-central,1954028,516070,869103753,2

Comment 3

[Darkspirit]

Duplicate of bug 1568152?

Comment 4

[Emilio Cobos Álvarez (:emilio)]

Yeah, seems way more likely to be due to the LTO changes for sure.

Comment 6

[Marian Raiciof [:marauder]]

Thanks for the details!