3.5. Job execution order

This system uses PBS Professional as its job scheduler.

Job execution order is controlled by PBS Professional’s Fairshare feature. Fairshare automatically calculates each user’s priority based on their historical computational resource usage. By prioritizing jobs from users with lower overall usage (i.e., higher priority), it prevents specific users from monopolizing resources and ensures fair access for everyone. Resource usage is calculated as “number of CPUs used × execution time.”

Note that in the priority calculation, recent usage is weighted to decay by half every 24 hours. Consequently, the longer a user goes without running jobs, the less impact their past usage has on their priority.