HP XC System 3.x Software - Manual (Page 49)

return 0;
}
The following is the command line used to compile this program:
$ cc hw_hostname.c -o hw_hostname
When run on the login node, it shows the name of the login node, n16 in this case:
$ ./hw_hostname
n16 says Hello!
When you use the srun command to submit this program, it runs on one of the compute nodes. In this
instance, it runs on node n13:
$ srun ./hw_hostname
n13 says Hello!
Submitting the same program again with the srun command may run this program on another node, as
shown here:
$ srun ./hw_hostname
n12 says Hello!
The srun can also be used to replicate the program on several cores. Although it is not generally useful,
it illustrates the point. Here, the same program is run on 4 cores on 2 nodes.
$ srun -n4 ./hw_hostname
n13 says Hello!
n13 says Hello!
n14 says Hello!
n14 says Hello!
The output for this command could also have been 1 core on each of 4 compute nodes in the SLURM
allocation.
5.3 Submitting a Parallel Job
When submitting a parallel job, you can specify the use of HP-MPI. You can also opt to schedule the job
by using SLURM. Depending on which submission method you choose, read the appropriate sections, as
follows:
• “Submitting a Non-MPI Parallel Job” (page 49)
• “Submitting a Parallel Job That Uses the HP-MPI Message Passing Interface” (page 50)
• “Submitting a Parallel Job Using the SLURM External Scheduler” (page 51)
5.3.1 Submitting a Non-MPI Parallel Job
to submit a parallel job
Use the following format of the LSF bsub command to submit a parallel job that does not make use of
HP-
MPI to an LSF-HPC node allocation ( compute node s). An LSF-HPC node allocation is created by the
-n num-procs parameter, which specifies the minimum number of cores the job requests.
bsub -n num-procs [bsub-options] srun [srun-options] jobname [job-options]
The bsub command submits the job to LSF-HPC.
The -n num-procs parameter, which is required for parallel jobs, specifies the number of cores requested
for the job. The num-procs parameter may be expressed as minprocs[,maxprocs] where minprocs
specifies the minimum number of cores and the optional value maxprocs specifies the maximum number
of cores.
5.3 Submitting a Parallel Job 49