Page Contents:

Page Group

How can a user influence job priority?

 -- deadline jobs
 -- posix priority
 -- resource reservation
 -- advance reservation



Job Scheduling

Resource Reservation: Preventing Large Parallel Job Starvation




The Problem


A Solution: Resource Reservation

  qsub -R y <scriptfile>

  qalter -R y <jobid>


Back Fill

Backfilling enables a lower-priority job to use resources that are blocked due to a resource reservation — but only if there is a runnable job whose prospective run time is small enough to allow the blocked resource to be used without interfering with the reservation.


Detecting/Monitoring/Spotting R-R Jobs which are in the Queue, Waiting

The Problem
If a larger job has a r-r it will block a smaller job from jumping past it in the queue and grabbing compute nodes as they become free. For example, two compute nodes may be free on which a waiting 24-slot job could run, but it will be blocked by an 48-slot r-r job. How is the owner of the 24-slot job to know?
Use qstat -j <job-num>
For example,
  prompt>qstat -j 80063
  .      . 
  .      . 
  reserve:                    y
  .      .
N.B. If the job has no r-r, then the output is NOT reserve: n; there is no reserve line in the output at all.
qstat -g c?
No! Shows only advance reservations, not resource reservations.