[webkit-qt] QtWebKit and SunSpider Benchmark: - are these expected results

Osztrogonác Csaba oszi at inf.u-szeged.hu
Tue Feb 19 09:06:45 PST 2013


Jocelyn, have you tried to enable DFG JIT and/or
LLINT on Windows? Both of them can speedup JSC.
But I have no idea how MSVC friendly the LLINT asm is ...

On my Linux box I got the following numbers a week before for SunSpider:
- interpreter (LLINT C-loop):   836 ms
- LLINT (asm):                  480 ms
- JIT:                          305 ms
- LLINT + JIT:                  193 ms
- LLINT + JIT + DFG-JIT:        140 ms


Jocelyn Turcotte írta:
> Hi Stan,
> Chrome uses V8, while other ports of WebKit, including Qt, use JavaScriptCore (Qt only uses V8 for QML).
> JavaScriptCore has similar performance to V8 on Mac after Apple implemented what they call DFG JIT.
> On Windows 32bit it still has basic JIT.
> On Windows 64bit it lags way behind, where it's still using the interpreter.
> This patch brings basic JIT support for Windows x64 and should be released with Qt 5.1: https://bugs.webkit.org/show_bug.cgi?id=107965
> This should be 2x-4x times faster than the interpreter according to my quick tests.
> But this still doesn't add support for DFG JIT, still only available on Mac and Linux, which would bring JS performances closer to Chrome's.
> So yes sadly I think that this kind of performance is currently expected on Windows x64 with Qt 5.0.
> Cheers,
> Jocelyn

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