Job Scheduling Priority: “Fair Share”

“Fair Share” assigns priority to jobs based on each project’s recent usage of the system. If a project has recently used a lot of CPU time, then the priority of their future jobs, relative to other projects, will be reduced. Once a job runs, it is allowed to complete and is unaffected by fair share.

Fair share only has an impact when there is contention for resources. Fair Share is calculated at a project level, so if one member of a project uses a lot of CPU time, future jobs submitted by that project will have lower priority.

Different queues (see the Job Queues section for a description of each queue) have different fair share weightings. The small, normal and large queues have a fair share weight of 10, which is considered to be the “standard” fair share weighting. The high memory and GPU queues, however, have a fair share weight of 50. If you request excessive resources (for example, too much memory), your job may be placed in a queue with a higher fair share weighting.

In addition to the above accumulation, fair share also decays with a “half-life” of 2 weeks. If you were to stop or reduce your use of Artemis, your fair share would decrease and the priority of your future jobs would increase.

Overall, it is best not to worry about fair share. The sooner you submit your jobs, the sooner they will run.