Bringing asm.js to the Chakra JavaScript engine in Windows 10

Re:Bringing asm.js to the Chakra JavaScript engine in Window... by realityking on Wednesday February 18, 2015 @03:07PM (#9070632)

Apparently Google's toying with the idea of using "use asm" as a signal to opt into TurboFan[1]. While not the AOT compilation envisioned by the asm.js creators, it speaks to the importance asm.js has already gained.

That said, personally I'd rather see time spend optimising the new ES6 features so they can be used without a big performance hit.

[1] https://code.google.com/p/v8/issues/detail?id=2599#c77

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Re:Bringing asm.js to the Chakra JavaScript engine in Window... by cpeterso on Wednesday February 18, 2015 @03:28PM (#9070726)

Mozilla tracks TurboFan performance on its "Are We Fast Yet?" benchmarks. TurboFan is clearly a work-in-progress because it is not scoring well on the common JS benchmarks:

http://arewefastyet.com/

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Re:Bringing asm.js to the Chakra JavaScript engine in Window... by reissbaker on Wednesday February 18, 2015 @07:55PM (#9071876)

To be fair, the arewefastyet benchmarks are intentionally very broad, and stress test many different parts of a JS engine. It may be the case that TurboFan has a very fast sweet spot for numeric code (which would explain why they'd want to use it for asm.js), but is slower for the more general cases.

I'd be interested to see how TurboFan performs on individual test cases; for example, Octane has several asm-specific tests, and based on their planning I wonder whether TurboFan is faster than Crankshaft for those individual tests even if it's slower for the rest of them.

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Re:Bringing asm.js to the Chakra JavaScript engine in Window... by bzbarsky on Wednesday February 18, 2015 @09:15PM (#9072091)

You can see breakdowns for various subtests on awfy. Of possible interest are http://arewefastyet.com/#machine=28&view=breakdown&suite=asm... and http://arewefastyet.com/#machine=28&view=breakdown&suite=asm... as well as http://arewefastyet.com/#machine=28&view=breakdown&suite=oct...

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Re:Bringing asm.js to the Chakra JavaScript engine in Window... by reissbaker on Thursday February 19, 2015 @01:45AM (#9072779)

Huh super interesting. It looks like currently TurboFan is competitive w/Crankshaft on the asm.js benchmarks, and much, much slower on everything else. I wonder if the V8 team expects TurboFan to someday beat Crankshaft on the asm benchmarks, given current perf differences.

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