| How do I specify the number of processors in an MPI job? |
| The MOAB implementation uses one of two methods to determine the topology of the multiprocessor job that you submit. The first matches the number of nodes that you request and the second matches the number of processors per node. MOAB on the FSUHPC has been configured to match jobs based on the number of processors per node. So, if you specify -l nodes=4:ppn=4, MOAB will not start your job until four nodes with four free processes are found. Instead, if you use -l nodes=16 to specify the number of processors you want, MOAB will match your job to any number of nodes with one or more free processors. The latter specification is much more likely to result in your job starting quickly. |
