1846267 - Specialise normal marking path to remove implicit edge checks

Status: RESOLVED FIXED

(Core :: JavaScript: GC, task, P1)

Description

[Jon Coppeard (:jonco)]

I found that specialising the normal marking path to remove the implicit edge checks was a performance win (I already did this for the parallel marking path).

This works by adding a new MarkingOptions enum and MarkingTracerT specialization that is used only when weak marking.

This improves splay and splay latency by 1.5% to 3% on macOS and Linux. Microbenchmarks focused on marking large list and tree data structures improved by 5% to 15%.

I'm not sure why this makes such a big difference but I suspect it's due to the implicit edge path being inlined into the marking code.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1846267 - Specialize normal marking path to remove implicit edge checks r?sfink

This works by adding a new MarkingOptions enum and MarkingTracerT
specialization that is used only when weak marking.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/fb4bb27720d6
Specialize normal marking path to remove implicit edge checks r=sfink

Comment 3

[Cristina Horotan [:chorotan]]

https://hg.mozilla.org/mozilla-central/rev/fb4bb27720d6