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Job Priority Factors

Multiple factors contribute to the priority of SLURM jobs. The jobs age, the resources it requests, the submitting user’s cluster utilization, and whether it was submitted to a buy-in account all contribute to the job’s priority.

Priority Factor Description Maximum Contribution to Priority
Age Starts at zero at job submission, then increases linearly to a maximum of 60000 after 30 days 60000 after 30 days
Fairshare Starts at 60000 and decreases and users' recent usage goes up. Usage for this calculation is decayed 50% each day 60000 for no recent cluster usage
Size Scales linearly with the amount of CPU and memory requested by a job. 100 per CPU, 20 per GB. 52000+ depending on memory requested
QOS Adds 1500 to buy-in jobs to ensure they are always above backfill schedulers minimum priority for reserving resources 1500

Backfill Scheduler Requirements to Reserve Resources

Minimum Priority of 1500

The backfill scheduler will not reserve future resources for jobs with an overall priority less than 1500. Jobs with a priority less than 1500 may be started immediately by the backfill scheduler if resources are available. Jobs submitted to buy-in accounts are always above this threshold.

Minimum Age of 30 Minutes

The backfill scheduler will not reserve future resources for jobs that have been queued for less than 30 minutes. Jobs queued for less than 30 minutes may be started immediately by the backfill scheduler if resources are available.