1546931 - installs.ini and profiles.ini should not be both stat'ed and read using main thread I/O during early startup

Status: RESOLVED FIXED

(Toolkit :: Startup and Profile System, defect, P2)

Description

[Florian Quèze [:florian]]

I thought we had fixed this in bug 1527704, but I saw a stat call for installs.ini reappear recently when updating my whitelist for the test in bug 1540135.

Here's a profile on the reference hardware on today's nightly: https://perfht.ml/2L4Rn87

Comment 1

[Dave Townsend [:mossop]]

This will have been caused by bug 1529879.

Comment 2

[Dave Townsend [:mossop]]

Thinking about this I think we can skip doing this stat check entirely...

Comment 3

[:Gijs (out for now; he/him)]

Given comment #2, I assume this is straightforward.

Comment 4

[Liz Henry (:lizzard) (relman/hg->git project)]

Too late for a fix in 68 at this point as we are a week away from 68 release.

Comment 5

[Florian Quèze [:florian]]

(In reply to Dave Townsend [:mossop] (he/him) from comment #2)

Thinking about this I think we can skip doing this stat check entirely...

I just saw this installs.ini stat be visible in a startup profile today: https://perfht.ml/2ZmGpxB

The only place in the code that seems to use this value is https://searchfox.org/mozilla-central/rev/38c88cbf4be87dfa0636d15a5d3599a8ea0d1a72/toolkit/profile/nsToolkitProfileService.cpp#656 I doubt this is needed during startup. Do we even need it at all?

Comment 6

[Dave Townsend [:mossop]]

No, as I alluded to in comment 2 I don't think we actually need the installs.ini stat at all (except for the rebuild case). installs.ini cannot change without profiles.ini changing first so the stat is pointless.

Comment 7

[Mandy Cheang [:mcheang][she/her]]

Attachment: Bug 1546931 - Remove installs.ini stat during early start-up on the main thread. r=mconley,mossop

Comment 8

[Mandy Cheang [:mcheang][she/her]]

This patch is not ready to land yet. I'm currently fixing a Xpcshell test failure for this patch:
https://treeherder.mozilla.org/#/jobs?repo=try&revision=3ef2b7e34360834eca12d2194c6649e11a72cf80

Comment 9

[Mandy Cheang [:mcheang][she/her]]

This is the most recent push to TRY: https://treeherder.mozilla.org/#/jobs?repo=try&author=mcheang%40mozilla.com&selectedJob=264306026

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/986d8d0e5af2
Remove installs.ini stat during early start-up on the main thread. r=mossop

Comment 11

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/986d8d0e5af2

Comment 12

[Liz Henry (:lizzard) (relman/hg->git project)]

Best to leave this to ride with nightly or do you think it is safe to uplift to early beta 70?

Comment 13

[Mike Conley (:mconley) (:⚙️)]

I don't think it's necessary to rush this - it can probably just stay on Nightly.

Comment 14

[Liz Henry (:lizzard) (relman/hg->git project)]

Thanks!