5 ms·

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

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

cpeterso 12y ago
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/ http://arewefastyet.com/
- reissbaker 12y ago
  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.
  - bzbarsky 12y ago
    You can see breakdowns for various subtests on awfy. Of possible interest are http://arewefastyet.com/#machine=28&view=breakdown&suite=asmjs-ubench http://arewefastyet.com/#machine=28&view=breakdown&suite=asm... and http://arewefastyet.com/#machine=28&view=breakdown&suite=asmjs-apps http://arewefastyet.com/#machine=28&view=breakdown&suite=asm... as well as http://arewefastyet.com/#machine=28&view=breakdown&suite=octane http://arewefastyet.com/#machine=28&view=breakdown&suite=oct...
    - reissbaker 12y ago
      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.

cpeterso 12y ago

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/ http://arewefastyet.com/

reissbaker 12y ago
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.
- bzbarsky 12y ago
  You can see breakdowns for various subtests on awfy. Of possible interest are http://arewefastyet.com/#machine=28&view=breakdown&suite=asmjs-ubench http://arewefastyet.com/#machine=28&view=breakdown&suite=asm... and http://arewefastyet.com/#machine=28&view=breakdown&suite=asmjs-apps http://arewefastyet.com/#machine=28&view=breakdown&suite=asm... as well as http://arewefastyet.com/#machine=28&view=breakdown&suite=octane http://arewefastyet.com/#machine=28&view=breakdown&suite=oct...
  - reissbaker 12y ago
    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.