1940066 - Compact arenas containing small buffer allocations

Status: RESOLVED FIXED

(Core :: JavaScript: GC, task, P2)

Description

[Jon Coppeard (:jonco)]

It's straightforward to implement compacting for small buffers (allocated in arenas). This may reduce memory use slightly.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1940066 - Allow compacting of small buffers allocated in arenas r?sfink

This makes the trace function for buffers take an indirect pointer and update
it if the target is moved as happens with existing edge tracing functions. This
is only supported for small buffers allocated in arenas.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/dc7ac99304af
Allow compacting of small buffers allocated in arenas r=sfink

Comment 3

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/dc7ac99304af

Comment 4

[Mayank Bansal]

(Standard disclaimer: Pending backfills and confirmation by sheriffs )
1.6% improvement on Base content JS opt fission
0.4% improvement on Base content explicit opt fission

Comment 5

[Florin Bilt]

(In reply to Sandor Molnar[:smolnar] from comment #3)

https://hg.mozilla.org/mozilla-central/rev/dc7ac99304af

Perfherder has detected a awsy performance change from push dc7ac99304af6879cefe595fc974c539717547fc.

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)
2%	Base Content JS	windows11-64-2009-shippable-qr	fission	1,573,440.00 -> 1,545,968.00
2%	Base Content JS	macosx1470-64-shippable	fission	1,568,245.82 -> 1,540,896.00

Details of the alert can be found in the alert summary, including links to graphs and comparisons for each of the affected tests.

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