1338208 - Nursery profiling information is wrong if the nursery is empty

Status: RESOLVED FIXED

(Core :: JavaScript: GC, defect)

Description

[Jon Coppeard (:jonco)]

We don't currently clear profileDurations_ in Nursery::collect so if the nursery is empty and we skip calling doCollection we will report the durations for the previous collection.

Comment 1

[Jon Coppeard (:jonco)]

This can be demonstrated by running:

$ JS_GC_PROFILE_NURSERY=0 ./shell -e 'a = []; for (let i = 0; i < 200000; i++) { a[i] = { x: i } } gc(); gc(); gc();'

The times given for e.g. marking the whole cell buffer are all the same for the last few collections.

Comment 2

[Jon Coppeard (:jonco)]

Attachment: bug1338208-nursery-profile

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/147e70a78d1a
Fix nursery profiling output if the nursery is empty r=sfink

Comment 4

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

https://hg.mozilla.org/mozilla-central/rev/147e70a78d1a