Subject: Re: [linux-audio-dev] DRC 2.4.0
From: Tim Goetze (tim_AT_quitte.de)
Date: Sun Feb 29 2004 - 01:35:48 EET
[Steve Harris]
>On Sat, Feb 28, 2004 at 11:57:27 +0200, Jussi Laako wrote:
>> On Sat, 2004-02-28 at 16:53, Steve Harris wrote:
>>
>> > Do you have the SIMD optimisations on, and have you tried the
>> > "halfcomplex" mode of FFTW, thats fine for audio, and saves some memory
>> > i/o.
>>
>> No, because SIMD optimizations are broken. I've been unable to compile
>> version which is able to run on all >=i686 platforms and includes 3DNow
>> &/ SSE stuff. It just crashed on my Thunderbird-core Athlon.
>
>I've only tried building for particular platforms (various SSE
>implementations), but it makes a big difference on PIII and Athlon XP.
on this 1.7 G athlon it does too, compare this:
[~/audio/src/fftw-3.0.1/tests] ./bench --verify irf1024
[~/audio/src/fftw-3.0.1/tests] ./bench irf1024
Problem: irf1024, setup: 89.29 ms, time: 11.50 us, ``mflops'': 2226.1
where irf = in-place real forward
... to Jussi's 2.4 G celeron:
>FFTW3:
>43 us / 1024 point complex FFT (single), 23256 FFTs/s, 23.814 MS/s
>70 us / 1024 point complex FFT (double), 14286 FFTs/s, 14.629 MS/s
>42 us / 1024 point real FFT (single), 23810 FFTs/s, 24.381 MS/s
tim
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