Welcome to the MPI

Debug Errors

srun

submit.slErrorDebughelloworld_mpi.c

#!/bin/bash -x
#SBATCH --job-name=helloworld_mpi
##SBATCH --mail-user="<your-email-address>"
##SBATCH --mail-type="ALL"
#SBATCH --time=00:00:10
#SBATCH --partition=parallel
#SBATCH --output=%x_%j.out
#SBATCH --nodes=2
#SBATCH --ntasks=10
#SBATCH --mem-per-cpu=1G
#SBATCH --constraint="IB"

# making sure we start with a clean module environment
module purge

echo "## Loading module"
ml purge; ml gnu9/9.4.0 openmpi4/4.1.1 ohpc config; ml list
# Compile program
mpicc helloworld_mpi.c -o helloworld_mpi

TEST_DIR=$(pwd)
echo "## Current dircectory $TEST_DIR"

echo "## Running test"
#Failure: srun errors while mpirun does not
#srun ./helloworld_mpi
#Success: testing with mpi version specific, works
srun --mpi=pmi2 ./helloworld_mpi
#Success: alternative command, but not needed because srun takes care of it
#mpirun -np $SLURM_NTASKS ./helloworld_mpi

echo "## Test finished. Goodbye"

--------------------------------------------------------------------------
The application appears to have been direct launched using "srun",
but OMPI was not built with SLURM's PMI support and therefore cannot
execute. There are several options for building PMI support under
SLURM, depending upon the SLURM version you are using:

version 16.05 or later: you can use SLURM's PMIx support. This
requires that you configure and build SLURM --with-pmix.

Versions earlier than 16.05: you must use either SLURM's PMI-1 or
PMI-2 support. SLURM builds PMI-1 by default, or you can manually
install PMI-2. You must then build Open MPI using --with-pmi pointing
to the SLURM PMI library location.

Please configure as appropriate and try again.
--------------------------------------------------------------------------

# Debug mpi
OMPI_MCA_pmix_base_verbose=10 srun ./helloworld_mpi

# Check mpi info
ompi_info

# Debug slurm
SLURM_DEBUG=2 srun --export="NCCL_DEBUG=INFO,NCCL_IB_DISABLE=1,PMIX_MCA_gds=hash" 
    --mpi=pmix_v4 -N 1 --ntasks=1 -w amd01n01 ./helloworld_mpi

# Verify mpi or pmix implementation
srun --mpi=list

# Run from login node
SLURM_DEBUG=2 srun --export="NCCL_DEBUG=INFO,NCCL_IB_DISABLE=1,PMIX_MCA_gds=hash" 
    --mpi=pmix -N 1 --ntasks=1 -w amd01n01 ./helloworld_mpi

#include <stdio.h>
#include <mpi.h>

int main (int argc, char *argv[])
{
int i, rank, size, processor_name_len;
char name [MPI_MAX_PROCESSOR_NAME];

MPI_Init (&argc, &argv);

MPI_Comm_size (MPI_COMM_WORLD, &size);
MPI_Comm_rank (MPI_COMM_WORLD, &rank);
MPI_Get_processor_name (name, &processor_name_len);

printf ("Hello World from rank %03d out of %03d running on %s!\n", rank, size, name);

if (rank == 0 )
    printf ("MPI World size = %d processes\n", size);

MPI_Finalize ();
return 0;
}