1697984 - Reserve stack capacity for CompilationGCOutput vectors

Status: RESOLVED FIXED

(Core :: JavaScript Engine, task, P1)

Description

[Ted Campbell [:tcampbell]]

For the same reasons as Bug 1689161, we should use inline vector capacity for CompilationGCOutput. Inlining 1 function and 1 scope should cover about 80% of delazifications.

In a simple delazification, we hit jemalloc 7 times:

1. LifoAlloc first chunk due to NewEmptyParserScopeData
2. ImmutableScriptData new
3. SharedImmutableScriptData new
4. CompilationGCOutput reserve functions == 1
5. CompilationGCOutput reserve scopes == 1
6. LiftParserScopeData
7. PrivateScriptData new

We should be able to remove number 4/5 with this simple change. Steps 2,3,6,7 form the JSScript representation and are not currently the parser's fault.

Comment 1

[Ted Campbell [:tcampbell]]

Attachment: Bug 1697984 - Reserve inline space in CompilationGCOutput vectors. r?arai!

Similar to what we do for CompilationStencil we should reserve a modest
amount of inline capacity to cover the bulk of delazifications.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b89925f96759
Reserve inline space in CompilationGCOutput vectors. r=arai

Comment 3

[Cristian Brindusan [:cbrindusan]]

https://hg.mozilla.org/mozilla-central/rev/b89925f96759