Administering Platform LSF - SAS

Chapter 2
How the System Works
Dispatch order
Viewing job order
in queue
Changing job
order in queue
(btop and bbot)
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 firstcome,
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.
Use bjobs to see the order in which jobs in a queue will actually be dispatched
for the FCFS policy.
Use the btop and bbot commands to change the job order in the queue.
See “Changing Job Order Within Queues” on page 117 for more information.
Administering Platform LSF 47