1488134 - 59.42% sccache requests_not_cacheable (linux64) regression on push 3fde5ca866c7 (Fri Aug 31 2018)

Status: RESOLVED WONTFIX

(Firefox Build System :: General, defect)

Description

[Ionuț Goldan [:igoldan]]

We have detected a build metrics regression from push:

https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=07abec90d85cb065f17ddb8f75adcc24be5f5f1f&tochange=3fde5ca866c7a6bc71b06fde4ddacf4137823422

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

Regressions:

 59%  sccache requests_not_cacheable linux64 lto debug taskcluster-m4.4xlarge     57.08 -> 91.00


You can find links to graphs and comparison views for each of the above tests at: https://treeherder.mozilla.org/perf.html#/alerts?id=15578

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

Comment 1

[Mike Hommey [:glandium]]

This is similar to bug 1487322. This enabled the clang plugin on more build jobs.

Comment 2

[Joel Maher ( :jmaher ) (UTC -8)]

I see the static constructors on mozilla-beta now:
== Change summary for alert #15663 (as of Mon, 03 Sep 2018 20:13:51 GMT) ==

Regressions:

 53%  compiler_metrics num_static_constructors linux64 lto debug     136.25 -> 208.00

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=15663

Comment 3

[Mike Hommey [:glandium]]

(In reply to Joel Maher ( :jmaher ) (UTC-4) from comment #2)
> I see the static constructors on mozilla-beta now:
> == Change summary for alert #15663 (as of Mon, 03 Sep 2018 20:13:51 GMT) ==
> 
> Regressions:
> 
>  53%  compiler_metrics num_static_constructors linux64 lto debug     136.25
> -> 208.00
> 
> For up to date results, see:
> https://treeherder.mozilla.org/perf.html#/alerts?id=15663

What does this have to do with this bug about sccache requests_not_cacheable ?

Comment 4

[Joel Maher ( :jmaher ) (UTC -8)]

this regression was seen on inbound/autoland and then merged to beta, it was labeled as related to this bug, maybe it isn't related- :glandium, should I file a new bug to look at the num-static-constructors?

Comment 5

[Mike Hommey [:glandium]]

It wasn't mentioned in this bug at all, so yes, please file a separate bug. I suspect the root cause is the same as bug 1487622 (as in clang plugin having codegen side effects).

Comment 6

[Mike Hommey [:glandium]]

(In reply to Mike Hommey [:glandium] from comment #5)
> I suspect the root cause is the same as bug 1487622 (as in clang plugin
> having codegen side effects).

I've now confirmed it to be the case. An LTO debug build with my WIP patch for bug 1487622 has 138 static constructors.

Comment 7

[Joel Maher ( :jmaher ) (UTC -8)]

oh, so it is something else, thanks for checking.

Comment 8

[Joel Maher ( :jmaher ) (UTC -8)]

hmm, looking in detail it is clearly bug 1487330 which is what this bug/regression is related to.

Comment 9

[Mike Hommey [:glandium]]

Expectedly, bug 1488631 brought it down. https://treeherder.mozilla.org/perf.html#/graphs?series=mozilla-inbound,1693236,1,2&selected=mozilla-inbound,1693236,376766,556377734