Platform LSF Administration Guide Version 6.2

Chapter 2

How the System Works

Administering Platform LSF

Dispatch order

Jobs are not necessarily dispatched in order of submission.

Each queue has a priority number set by an LSF Administrator when the queue is

defined. LSF tries to start jobs from the highest priority queue first.

By default, LSF considers jobs for dispatch in the following order:

◆

For each queue, from highest to lowest priority. If multiple queues have the same

priority, LSF schedules all the jobs from these queues in first-come, first-served

order.

◆

For each job in the queue, according to FCFS order

◆

If any host is eligible to run this job, start the job on the best eligible host, and mark

that host ineligible to start any other job until JOB_ACCEPT_INTERVAL has

passed

Jobs can be dispatched out of turn if pre-execution conditions are not met, specific hosts

or resources are busy or unavailable, or a user has reached the user job slot limit.

Viewing job order

in queue

Use bjobs to see the order in which jobs in a queue will actually be dispatched for the

FCFS policy.

Changing job order in queue (btop and bbot)

Use the btop and bbot commands to change the job order in the queue.

See “Changing Job Order Within Queues” on page 145 for more information.