1351306 - huge deviation between changests included in Linux nightly builds and same day Windows nightly builds.

Status: RESOLVED FIXED

(Release Engineering :: General, defect)

Description

[Bill Gianopoulos [:WG9s]]

OK. The issue here is that Taskcluster builds are done on systems based on UTC and buildbot builds are done on systems on US/Pacific time.

So during the winter, taskcluster builds were designed to kick-off at the same time as the buildbot builds, but now that the buildbot builds kick off an hour earlier because of so called Daylight Saving time, they are completely out of sync.

So I would like to propose that taskcluster builds be based off the state of mozilla-central at 10:02.

That rationale is that by the next Daylight Saving time transition all builds will be on Taskcluster, and also that delaying the already arrive too late in US/Easter ntimezone by an additional hour in the summer is not acceptable.

The current situation is that often because of the normal merge time performed by sherrifs is after the 3:02 pacific time kickoff of buildbot nightlies and the next hour is the window in which merges between central inbound autoland and fx normally occur.

The corrent situation results in Widows nightly builds having more affinity to the previous days Linux builds than to the same day.

Comment 1

[Justin Wood (:Callek)]

Attachment: Bug 1351306 - Move the UTC starttime of nightlies earlier.

This is needed because we want to keep the nightly start times aligned with Buildbot starts, in order to keep the possibility of drastically different code going out for one platform in a day and not another (e.g. a merge).  The reason the change is needed specifically is because UTC of course doesn't follow Daylight Time shifts, and Pacific time just went through one (+1 hour) which brings it closer to UTC by one hour, so in order to keep UTC matching what buildbot uses we subtract 1 hour from the UTC time.

Review commit: https://reviewboard.mozilla.org/r/124254/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/124254/

Comment 2

[Rail Aliiev [:rail]]

Comment on attachment 8852006 [details]
Bug 1351306 - Move the UTC starttime of nightlies earlier.

https://reviewboard.mozilla.org/r/124254/#review126804

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3a10b2084b4a
Move the UTC starttime of nightlies earlier. r=rail

Comment 4

[Justin Wood (:Callek)]

https://hg.mozilla.org/releases/mozilla-aurora/rev/d32e5470aa322368f4a141fb41583a2a0e07d922

Comment 5

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/3a10b2084b4a