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SLURM Reference Manual

Comparison with POE

SRUN and AIX's POE (Parallel Operating Environment) both use UNIX environment variables to manage the resources for each parallel job that they run. Of course, variables with comparable roles have different names under each system (and both systems have many other environment variables for other purposes too).

Three differences in detail between environment-variable use by SRUN and POE are noteworthy:

  • SRUN assigns values to its resource-management variables by means of its own interactive options, one option for each environment variable (plus extra control options, such as -j). Instead, POE uses the usual SETENV or EXPORT utilities to assign values to its environment variables.
  • POE's LoadLeveler ignores many environment variables when it run batch jobs under AIX on LC machines. SLURM does not ignore the corresponding environment variables when set by SRUN, even for batch runs.
  • On LC Linux clusters, the completion of your SLURM-managed batch job on any compute node(s) also automatically terminates any accompanying interactive processes run by you on those same compute nodes (a policy started in August, 2007). Such processes may continue to run on AIX machines. See the "User Impact" section above for details.

This chart lists the SLURM (SRUN-set or inferred) resource-management environment variables for which direct POE counterparts exist. For an explanatory inventory of all SLURM environment variables, see the separate section below.

To Set

Total processes to run -n SLURM_NPROCS MP_PROCS(*)
Total nodes allocated -N SLURM_NNODES MP_NODES(*)
Node list for this job (inferred) SLURM_NODELIST MP_SAVEHOSTFILE(*)
MP ID of current process (inferred) SLURM_PROCID MP_CHILD
Output mode choice -o (lc) SLURM_STDOUTMODE MP_STDOUTMODE
Partition for this job -p SLURM_PARTITION MP_RMPOOL(*)
Debug message level -d SLURMD_DEBUG MP_INFOLEVEL
Output message level -v (lc) SLURM_DEBUG MP_INFOLEVEL
Output label choice -l SLURM_LABELIO MP_LABELIO

(*)Ignored by LoadLeveler for batch jobs on AIX machines at LC.

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