[gmx-users] Parallel FFTW performance

Bing Kim abinitiomd at hotmail.com
Sun Oct 26 22:46:01 CET 2003

Hi All!

I am sorry this question is not for Gromacs exactly but for FFTW.
But this question would raise on Gramacs too.
I recently installed FFTW-2.1.5 which can use MPI.
It was compiled with gcc-3.3.2 and mpich-
When I ran a benchmark test program, rfftw_mpi_test, which is located in 
I found that its performace is worse in dual cpus than single cpu.
Basically, communication cost should be zero in SMP machine.. that I 
So.. I wonder if gromacs use rfftw_mpi, how it can get speed up in multiple 
Please help me understand this thing.

Bing Kim

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