1665984 - Determine why fission is restricted to mozilla-central tasks

Status: RESOLVED WORKSFORME

(Testing :: Raptor, task, P2)

Description

[Greg Mierzwinski [:sparky]]

Fission task variants are currently restricted to tests which run on mozilla-central: https://searchfox.org/mozilla-central/source/taskcluster/taskgraph/transforms/tests.py#165-170

This bug is to determine why, and make a change if necessary. The reason I'm looking at this is because I wanted to make a nightly cron task for our browsertime fission+non-fission tests but I can't because I would have to run non-fission tests on each mozilla-central commit.

:ahal, I see that you made the filter, would you know why this restriction exists?

Comment 1

[Andrew Halberstadt [:ahal]]

Any test that doesn't run on central is effectively disabled, since we don't guarantee that it passes on the latest nightly builds. So I think this check was just to make sure that we aren't enabling fission for broken tasks that might make it harder for the fission team to triage.

I'm not really clear why that would restrict you, but maybe you could make a new variant that is like fission but then doesn't apply that central filter? Though I don't really understand why that filter means you would have to run non-fission tests on each mozilla-central commit or why that would be a problem..

Comment 2

[Greg Mierzwinski [:sparky]]

Ah I see, thanks for the context!

(In reply to Andrew Halberstadt [:ahal] from comment #1)

I'm not really clear why that would restrict you, but maybe you could make a new variant that is like fission but then doesn't apply that central filter? Though I don't really understand why that filter means you would have to run non-fission tests on each mozilla-central commit or why that would be a problem..

It's because the filter kicks out all fission tasks if they don't have mozilla-central in the run-on-projects settings (we can't define these for try runs only because of this as well): https://searchfox.org/mozilla-central/source/taskcluster/taskgraph/transforms/tests.py#1359-1360

It's not really a problem but I wanted to minimize the amount of test load I was adding. I'll make a new variant for this if we need it though - we decided to run the browsertime normal/fission on each mozilla-central commit.

Comment 3

[Chris Peterson [:cpeterson]]

Tracking Raptor Fission work for Fission Nightly milestone (M6c).