[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