[mpich-discuss] MPI_Comm_spawn crosses node boundaries

[Mccall, Kurt E. (MSFC-EV41)]

Hi,

Running MPICH under Slurm, MPI_Comm_spawn unexpectedly creates new processes on any and all of the nodes that Slurm allocates to the job.   I would like it to only create new processes locally on the node that called MPI_Comm_spawn.

I've tried passing MPI_Comm_spawn an info struct created like this:

        MPI_Info info;
        MPI_Info_create(&info);
        MPI_Info_set(info, "host", host_name);
        MPI_Info_set(info, "bind_to", "core");

where hostname = "n001" or even the full name "n001.cluster.pssclabs.com"

but that doesn't prevent the problem.  Any suggestions?

Thanks,
Kurt
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