2043996 - Try presizing nursery string deduplication hash table

Status: NEW

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

Description

[Jon Coppeard (:jonco)]

Investigations indicate that a significant amount of nursery GC time during the speedometer3 benchmark can be attributed to string deduplication. Growing the hash table involves rehashing existing entries and may account for a reasonable fraction of this. Pre-sizing the table, perhaps to the size used by last minor GC could help here. We could also try only doing this when GCs are occurring frequently.

Comment 1

[Steve Fink [:sfink] [:s:]]

A more memory-hungry variant would be clearing without freeing the previous hashtable, to avoid the free/alloc entirely. We'd still want to free it on a shrinking GC.

Comment 2

[Worcester12345]

Please add "PERF" key word.
Thank you.