1251076 - Record ccache stats in build telemetry data

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[Dan Minor [:dminor]]

Using ccache can have a big effect on build times. We should capture whether ccache is enabled and the relevant stats in the build telemetry data.

Comment 1

[Dan Minor [:dminor]]

Attachment: MozReview Request: Bug 1251076 - Record ccache stats in build telemetry data r?gps

Using ccache can have a big impact on compile times but we don't currently
capture ccache statistics.

Review commit: https://reviewboard.mozilla.org/r/36667/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/36667/

Comment 2

[Gregory Szorc [:gps]]

Comment on attachment 8723675 [details]
MozReview Request: Bug 1251076 - Record ccache stats in build telemetry data r?gps

https://reviewboard.mozilla.org/r/36667/#review33211

We should also capture MOZ_USING_CCACHE from substs.

Comment 3

[Gregory Szorc [:gps]]

https://reviewboard.mozilla.org/r/36667/#review33211

And should make ccache stats conditional on ccache being enabled.

Comment 4

[Dan Minor [:dminor]]

Comment on attachment 8723675 [details]
MozReview Request: Bug 1251076 - Record ccache stats in build telemetry data r?gps

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/36667/diff/1-2/

Comment 5

[Gregory Szorc [:gps]]

Comment on attachment 8723675 [details]
MozReview Request: Bug 1251076 - Record ccache stats in build telemetry data r?gps

https://reviewboard.mozilla.org/r/36667/#review33321

::: python/mozbuild/mozbuild/mach_commands.py:517
(Diff revision 2)
> +                for key in [key[0] for key in ccache_end.STATS_KEYS]:

We should be using ccache_diff, which is assigned above. We record ccache stats at beginning of build then generate a delta against at end of build. These deltas are more useful than the raw values. Although the __sub__ implementation of the ccache class does preserve some absolute values like cache capacity.

Comment 6

[Dan Minor [:dminor]]

Comment on attachment 8723675 [details]
MozReview Request: Bug 1251076 - Record ccache stats in build telemetry data r?gps

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/36667/diff/2-3/

Comment 7

[Gregory Szorc [:gps]]

Comment on attachment 8723675 [details]
MozReview Request: Bug 1251076 - Record ccache stats in build telemetry data r?gps

https://reviewboard.mozilla.org/r/36667/#review33821

Comment 8

[Dan Minor [:dminor]]

Comment on attachment 8723675 [details]
MozReview Request: Bug 1251076 - Record ccache stats in build telemetry data r?gps

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/36667/diff/3-4/

Comment 9

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/51e6f2f2307b

Comment 10

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/51e6f2f2307b