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From: Tahir Malas (tmalas_at_[hidden])
Date: 2007-05-28 08:00:32


Hi all,
We have an 8-node cluster of SMP nodes, which have dual-quad core
processors. The network is Infiniband. Each process in our parallel FORTRAN
90 program holds an identical array that is used in all parts of the
program. However, when the size of the problem gets larger and larger, this
memory cost has started to become a memory bottleneck for us.
If all 8 processes in the same node could just read from the same memory
instead of holding their arrays, we would have significant memory gain. This
would be natural in a node if were to use OpenMP, but I wonder whether this
is somehow possible with only MPI? We know that passing to hybrid
programming (MPI + OpenMP) is a choice, but we look for simpler choices for
the time being.
In another post I have seen something like "you could share the memory
between processes using the shm_xxx system calls of unix", but this isn't
clear to me.
Thanks in advance,

Tahir Malas
Bilkent University
Electrical and Electronics Engineering Department
Phone: +90 312 290 1385