1917338 - Cache allocSite values across page-loads

Status: NEW

(Core :: JavaScript: GC, enhancement, P3)

Description

[Matthew Gaudet (he/him) [:mgaudet]]

Allocation sites help quite a bit by ensuring we pre-tenure values we expect to be long lived. However, the predictions are per-pageload and have to be rediscovered each time.

We've had quite a bit success with JitHints, which caches warmup across page loads.

We likely want something similar for allocation sites.

Comment 1

[Matthew Gaudet (he/him) [:mgaudet]]

Dennis has a patch here which might be a good basis to build upon.

Comment 2

[Mayank Bansal]

based on https://bugzilla.mozilla.org/show_bug.cgi?id=1917031#c1, should this bug be prioritized higher?

Comment 3

[Markus Stange [:mstange]]

We are no longer seeing Minor GC running during the measured time of sp3 (at least on Windows), so that lowers the priority here.