[Webkit-unassigned] [Bug 73789] Need SSE optimization for SincResampler::Process()

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=73789





--- Comment #22 from xingnan.wang at intel.com  2011-12-06 17:19:39 PST ---
(In reply to comment #21)
> (From update of attachment 118008 [details])
> View in context: https://bugs.webkit.org/attachment.cgi?id=118008&action=review
> 
> > Source/WebCore/platform/audio/SincResampler.cpp:260
> > +#ifdef __SSE2__
> 
> I think visually, it might make more sense to stick the entire #ifdef __SSE2__ code inside the original
>  {
>    float input;
>    ...
>  }
> 
> So we get something like
>  {
>    float input;
> #ifdef __SSE2__
>    ...
> #else
>    <original code>
> #endif
>  }
> 
> > Source/WebCore/platform/audio/SincResampler.cpp:282
> > +#define CONVOLVE_4_SAMPLE                    \
> 
> Nit:  Probably should be named CONVOLVE_4_SAMPLES (plural, not singular).
> 
> > Source/WebCore/platform/audio/SincResampler.cpp:293
> > +                    mInput = _mm_load_ps(inputP);
> 
> I might consider adding a new macro
> 
> #define LOAD_DATA(l1, l2) \
>   mInput = mm_load_ps(inputP); \
>   mK1 = _mm_##l1_ps(k1); \
>   mK2 = _mm_##l2_ps(k2)
> 
> Then here we can say
>   LOAD_DATA(load, load);
> 
> And below, we can have
>   LOAD_DATA(loadu, load);
>   LOAD_DATA(load, loadu);
>   LOAD_DATA(loadu, loadu);
> 
> This makes it easy to see that they're all the same except whether we do aligned or unaligned loads.
> 
> (I didn't test this code; some minor changes might be needed.)
> 
> > Source/WebCore/platform/audio/SincResampler.cpp:327
> > +            groupSumP = reinterpret_cast<float*>(&sums2);
> 
> I think I'd write the above as
> 
> sum1 += groupSumP[0];
> sum1 += groupSumP[1];
> sum1 += groupSumP[2];
> sum1 += groupSumP[3];
> 
> Or maybe just sum1 += groupSumP[0] + groupSumP[1] + groupSumP[2] + groupSumP[3]
> 
> Same for sum2 below.

Hi Raymond,
    Thanks your good comments, I`ll update it.

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