Re: fftw: Usage of SSE in 64bit?

[Julian Taylor <jtaylor.debian@googlemail.com>]

On Wed, Mar 23, 2011 at 3:27 PM, Charles G Montgomery <cgm@physics.utoledo.edu> wrote:

On Wednesday 23 March 2011 9:52:27 am Carsten Aulbert wrote:
> 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).
>
> As this is very often used in science, I thought people might know
> why this was chosen.
>
> Cheers
>
> Carsten

I wonder if this might have anything to do with the bug I just submitted
for fftw3-3
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=619324
That seems a 64bit problem not seen for 32bit.

regards   cgm

I have just tested this with fftw3 built explicitly with sse enabled on 64 bit.

It does not fix the issue.

backtrace:

#0 0x0000000000401903 in dfftw_execute_ (p=0x7fffffffe460) at f77funcs.h:27
#1 0x0000000000401730 in badfftw3 () at test.f90:40
#2 0x00000000004014ba in main ()
#3 0x00007ffff72f1c4d in __libc_start_main (main=<value optimized out>, argc=<value optimized out>, ubp_av=<value optimized out>, init=<value optimized out>,
fini=<value optimized out>, rtld_fini=<value optimized out>, stack_end=0x7fffffffe578) at libc-start.c:226
#4 0x00000000004013c9 in _start ()