[Beowulf] MPICH question

[John Lau]

Hi,

I have a question on the number of processes spawned by MPICH. I am
using MPICH 1.2.5.2 --with-device=ch_p4. When I use mpirun -np 4 to
start a mpi process, total 8 processes will be spawned. But only 4
processes have loadings on CPUs. I would like to know if it is the
correct behavior of MPICH? And what's the use of the 4 no-loading
process? Thank you.

Best regards,
John Lau

-- 
John Lau Chi Fai
Center For Large-Scale Computation
Tel: (852) 2994-3727
Fax: (852) 2994-2101