Slurm Fairshare Score

Fairshare and Equitable Use of the Supercomputer

Computational resources on the supercomputer are free for ASU faculty, students, and collaborators. To keep availability equitable, submitted jobs in the queue are prioritized based on recent usage via the submitting user’s Fairshare score, which scales a base priority by a factor dependent on recent usage from zero to one. A user’s fairshare halves for every 10,000 core-hour equivalents (CHE) of usage, e.g., 20,000 CHE consumed today would reduce a user’s fairshare to 0.25. More specifically, FairShare = 2^{-current_core_hour_equivalent_usage / 10,000}.

Usage is “forgotten” at an exponential rate, with a half-life of one week. For instance 20,000 CHE consumed today would be “remembered” as 10,000 a week from now, and after 26 weeks, as 1.07 core-second equivalents. For more details on the way fairshare is dynamically controlled on RC’s systems, see this 2020 PEARC proceedings paper.

CHE are tracked based on a linear combination of different hardware allocations, i.e.,

Thus, utilizing a single core with four GiB of RAM and one A100 GPU for four hours would equate to approximately 108 CHE. Researchers who carefully manage their hardware allocations to maximize job efficiency (see our documentation page on seff and mysacct for tools to track efficiency) will experience less impact on their FairShare.