[Beowulf] Sharing an array in an MPI program?

[Greg Lindahl]

On Thu, May 24, 2007 at 06:05:03PM +0300, Tahir Malas wrote:

> 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.

This is actually a fairly frequent question.

Some people use hybrid MPI+OpenMP in this situation. However, another
way to attack it is to create a shared memory segment and put this
array into it. Or, alternately, you can mmap() a file into all the
processes with this data.

-- greg