# Core Specialization

Core Specialization is a feature designed to isolate system overhead (system interrupts, etc.) to designated cores on a compute node. This can reduce applications interrupts ranks to improve completion time. The job will be charged for all allocated cores, but will not be able to directly use the specialized cores.

## Command Options

All job allocation commands (salloc, sbatch and srun) accept the -S or --core-spec option with a core count value (e.g. "-S 1" or "--core-spec=2"). The count identifies the number of cores to be reserved for system overhead on each allocated compute node. The core specialization count can be viewed using the scontrol, sview and squeue commands. Use the squeue command with the "%X" format option to see the count (it is not reported in the default output format). The scontrol and sview commands can also be used to modify the count for pending jobs.

## System Configuration

Core Specialization is only supported if SelectType is configured as either select/cons_res or select/cray. A job's core specialization option will be silently cleared on other configurations.

Last modified 5 November 2013