1515087 - Make it possible to gather a measurement of browser start-up from cold OS boot

Status: RESOLVED DUPLICATE of bug 1554314

(Testing :: Talos, enhancement, P3)

Description

[Mike Conley (:mconley) (:⚙️)]

Right now, we have a number of tests that measure things related to start-up. ts_paint is one. tp5n actually gathers something like this too[1], measuring time to sessionstore-windows-restored.

These tests, however, tend to run when the browser has already been started in the same OS boot session.

Talos automatically creates and loads a session before running any tests, to run the "getInfo" step, to determine things about the environment it's running on.

This has the effect of loading DLLs, warming the disk cache, etc. This means that what ts_paint and tp5n effectively measure is "warm start-up", since the browser had already been running earlier.

My hypothesis is that most users on the release channel tend to experience "cold startup" for Firefox, where the OS has very recently booted. I'd like to measure that cold startup time if possible.

jmaher, rwood and I were talking about this, and we think it might be possible to do this without any special Taskcluster gymnastics. Since the Talos machines are restarted frequently (although, not necessarily between Talos test runs), we could try to add a check to see if Firefox was ever running within the current OS session, and if not, run a separate test or take a separate measurement before running any other tests.

The test results might be noisier than other Talos tests here, since they'll run less frequently. I'm not even sure how we'd even queue up this kind of test to run on try. But I guess that's what we can figure out in this bug.



[1]: https://treeherder.mozilla.org/perf.html#/graphs?series=mozilla-central,1776888,1,1

Comment 1

[Dave Hunt [:davehunt] [he/him] ⌚BST]

:mconley is this likely to be covered by the capture-card work that's happening in Q3? That's not specifically Talos, so I just wanted to check if Talos is a requirement there.

Comment 2

[Mike Conley (:mconley) (:⚙️)]

Yeah, I think this is basically a dupe of bug 1554314 now - I don't think we're going to be using Talos.