Bug 235996 – Speed-up JSON.stringify() by avoiding "toJSON" property lookups

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Alexey Shvayka]

Speed-up JSON.stringify() by avoiding "toJSON" property lookups

[Alexey Shvayka]

Created attachment 450601 [details]
Patch

[Alexey Shvayka]

(In reply to Alexey Shvayka from comment #1)
> Created attachment 450601 [details]
> Patch

                                              r288790                   patch

json-stringify-empty-array               109.4195+-0.3423     ^     89.3711+-0.2926        ^ definitely 1.2243x faster
json-stringify-array-replacer             26.5174+-0.0323           26.5100+-0.0257
json-stringify-many-objects              243.2980+-2.4751     ^    228.2883+-0.8872        ^ definitely 1.0657x faster
json-stringify-many-objects-to-json      170.5229+-0.3290     ^    152.2288+-0.4103        ^ definitely 1.1202x faster
vanilla-todomvc-json-stringify           192.3345+-0.4409     ^    185.5248+-0.2852        ^ definitely 1.0367x faster

[Alexey Shvayka]

Comment on attachment 450601 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=450601&action=review

> Source/JavaScriptCore/ChangeLog:9
> +        it accounts for 10-15% of running time. EmberJS* subtests rely on JSON.stringify() as

MacBookPro17,1:

VanillaJS-TodoMVC: 50ms
Vanilla-ES2015-TodoMVC: 65ms

JSON.stringify() takes 5-10ms, way slower on MiniBrowser than JSC shell for some reason.

[Saam Barati]

Comment on attachment 450601 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=450601&action=review

> Source/JavaScriptCore/ChangeLog:20
> +        While we could come up with a solution that doesn't involve creating StructureRareData
> +        for all structures we stringify, like keeping a list of StructureIDs w/o "toJSON" method,
> +        which will be correct as long as `m_hasFastObjectProperties || m_isJSArray` is true for all
> +        seen objects, that would probably miss some edge case, won't persist between JSON.stringify()
> +        calls, and won't speed-up structures with "toJSON" methods like Dates.

Can you also include what your solution actually was, instead of potential alternate solutions? And how it works

[Alexey Shvayka]

Created attachment 450648 [details]
Patch

Expand ChangeLog on actual solution and handle CachedSpecialPropertyKey::ToJSON in more places.

[Saam Barati]

Comment on attachment 450648 [details]
Patch

r=me

[Alexey Shvayka]

Comment on attachment 450648 [details]
Patch

Thank you Saam!

[EWS]

Committed r289020 (246728@main): <https://commits.webkit.org/246728@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 450648 [details].

[Radar WebKit Bug Importer]

<rdar://problem/88409665>