877021 - Speed up CreateRegExpMatchResult()

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Sean Stangl [:sstangl]]

Attachment: patch

This makes roughly the same change as in Bug 876976, which affected .match(), but this time it affects .exec() and therefore affects that jQuery benchmark I intended to speed up in the first place.

Comment 1

[Sean Stangl [:sstangl]]

Attachment: microbenchmark

Microbenchmark.

SM (unpatched): 630ms
SM (patched): 220ms
V8 (release): 210ms

Comment 2

[Boris Zbarsky [:bzbarsky]]

That helps a bit.  On the testcase in bug 876846 it takes my times from about 1450ns/iteration to about 1300ns/iteration.

If I comment out these two calls, however:

    if (!SetPropertyHelper(cx, array, cx->names().index, index))
    if (!SetPropertyHelper(cx, array, cx->names().input, inputVal))

then I get something closer to 800ns/iteration.

Note that in the regexp in that testcase there aren't that many parens in the regexp...

Comment 3

[Boris Zbarsky [:bzbarsky]]

Those should be using a define, not a set, btw, per spec... But using DefineNativeProperty doesn't seem to help too much in terms of performance.

A lot of the time here seems to be doing updateSlotsForSpan and whatnot...

Can we somehow preallocate this array with the right shape and slots?

Comment 4

[Sean Stangl [:sstangl]]

(In reply to Boris Zbarsky (:bz) from comment #3)
> Can we somehow preallocate this array with the right shape and slots?

Yeah, I'll look into that next.

Comment 5

[Sean Stangl [:sstangl]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/b920312f99e3

Comment 6

[Ryan VanderMeulen [:RyanVM]]

Backed out for xpcshell orange.
https://hg.mozilla.org/integration/mozilla-inbound/rev/278c0a105f8d

https://tbpl.mozilla.org/php/getParsedLog.php?id=23621016&tree=Mozilla-Inbound

Comment 7

[Ryan VanderMeulen [:RyanVM]]

Gah, that was the wrong one to backout. You can re-land. Sorry about that :(

Comment 8

[Ryan VanderMeulen [:RyanVM]]

Re-landed. Sorry again for the mix-up.
https://hg.mozilla.org/integration/mozilla-inbound/rev/782759aa8a03

Comment 9

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/782759aa8a03

Comment 10

[Boris Zbarsky [:bzbarsky]]

Sean, is there another bug tracking comment 4?

Comment 11

[Sean Stangl [:sstangl]]

Yes, filed Bug 879402.