Queues

LoadLeveler is IBM's batch scheduler. It uses a backfill algorithm which runs shorter jobs ahead of  longer jobs if the available nodes would otherwise sit idle. Otherwise scheduling of jobs is first come, first served. We have defined six job queues to serve this cluster.
 

If your job control file does not specify a time limit the default (often short) time limit indicated will be used. It is necessary to tell the scheduling system a reasonable upper bound on how long your job will run, otherwise it would assume the maximum runtime allowed by the queue which would cause the scheduler to put unnecessary holds jobs which are waiting for CPUs to become available.

Queues