[MPICH2-dev] running out of fd's?

[Nicholas Karonis]

Hi,

I just installed MPICH2-1.0.6 on Mac OS X 10.5.1 (i.e., Leopard).
I configured it with the gforker and it was all compiled using
Gnu's C and C++ compilers that came with the developer tools
on the Mac OS X disk.

The build seem to go OK and so I tried testing it with a small
ring program (source at bottom).  When I run the ring with -np 75
all is OK but when I increase it to 100 I get an error message:

/* running with 75, all OK */
mpro% mpiexec -np 75 ring
nprocs 75 received 75

/* attempting to run with 100, problem :-( */
mpro% mpiexec -np 100 ring
Error in system call select: Bad file descriptor
mpro%

Any suggestions?

Thanks in advance,
Nick


--- app source
mpro% cat ring.c
#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
     int nprocs, myid;
     int val;
     MPI_Status st;

     MPI_Init(&argc, &argv);

     MPI_Comm_size(MPI_COMM_WORLD, &nprocs);

     if (nprocs > 1)
     {
	MPI_Comm_rank(MPI_COMM_WORLD, &myid);
	if (myid == 0)
	{
	    val = 1;
	    MPI_Send(&val, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
	    MPI_Recv(&val, 1, MPI_INT, nprocs-1, 0, MPI_COMM_WORLD, &st);
	    printf("nprocs %d received %d\n", nprocs, val);
	}
	else
	{
	    MPI_Recv(&val, 1, MPI_INT, myid-1, 0, MPI_COMM_WORLD, &st);
	    val ++;
	    MPI_Send(&val, 1, MPI_INT, (myid+1)%nprocs, 0, MPI_COMM_WORLD);
	} /* endif */
     } /* endif */

     MPI_Finalize();
     exit(0);

} /* end main() */
mpro%