On Wed, Mar 23, 2011 at 3:56 PM, Sylvestre Ledru <[email protected]>wrote:
> Le mercredi 23 mars 2011 à 15:53 +0100, Julian Taylor a écrit : > > On Wed, Mar 23, 2011 at 3:21 PM, Sylvestre Ledru > > <[email protected]> wrote: > > Le mercredi 23 mars 2011 à 14:52 +0100, Carsten Aulbert a > > écrit : > > > Hi > > > > > > we are just discussing FFTW in our institute and we hit this > > bug reported to > > > Ubuntu which also holds true for Debian: > > > > > > https://bugs.launchpad.net/ubuntu/+source/fftw3/+bug/602586 > > > > > > Is there a specific reason why SSE is enabled for 32bit and > > not enabled for > > > 64bit as the difference in performance can easily be a > > factor of 2 (on 64bit). > > > > This bug is invalid. SSE is enabled by default under amd64 [1] > > > > Sylvestre > > [1] > > > http://gcc.gnu.org/onlinedocs/gcc/i386-and-x86_002d64-Options.html > > `sse' > > [...] > > "This is the default choice for the x86-64 compiler." > > > > > > > > > > but it will not define HAVE_SSE in config.h so the fftw3 might not use > > some handcrafted functions. > Are you sure that gcc under amd64 is not defining HAVE_SSE > transparently ? > > Sylvestre > > > I would be very suprised when gcc defines HAVE_SSL which is a flag usually set by configure. It does not in gcc 4.4.3 64 bit (ubuntu 10.04): fftw3-3.2.2/simd/nonportable> gcc -std=gnu99 -DHAVE_CONFIG_H -I. -I../.. -I../../kernel -I../../simd -g -Wall -O2 -pthread -MT sse.lo -MD -MP -MF .deps/sse.Tpo -c -E sse.c | grep fftwf_check_alignment_of_sse_pmpm on a 32 bit build (gcc 4.4.5 HAVE_SSE defined by package): fftw3-3.2.2/simd/nonportable> gcc -std=gnu99 -DHAVE_CONFIG_H -I. -I../.. -I../../kernel -I../../simd -g -Wall -O2 -pthread -MT sse.lo -MD -MP -MF .deps/sse.Tpo -c -E sse.c | grep fftwf_check_alignment_of_sse_pmpm void fftwf_check_alignment_of_sse_pmpm(void)
