LSF Version 7.3 - Administering Platform LSF

Job Slot Limits For Parallel Jobs
502 Administering Platform LSF
◆ Submit a job with a host list:
bsub -n 4 blaunch -z "hostA hostB" myjob
◆ Submit a job with a host file:
bsub -n 4 blaunch -u ./hostfile myjob
◆ Submit a job to an application profile
bsub -n 4 -app pjob blaunch myjob
Job Slot Limits For Parallel Jobs
A job slot is the basic unit of processor allocation in LSF. A sequential job uses one
job slot. A parallel job that has N components (tasks) uses N job slots, which can
span multiple hosts.
By default, running and suspended jobs count against the job slot limits for queues,
users, hosts, and processors that they are associated with.
With processor reservation, job slots reserved by pending jobs also count against all
job slot limits.
When backfilling occurs, the job slots used by backfill jobs count against the job slot
limits for the queues and users, but not hosts or processors. This means when a
pending job and a running job occupy the same physical job slot on a host, both
jobs count towards the queue limit, but only the pending job counts towards host
limit.
Specifying a Minimum and Maximum Number of Processors
When submitting a parallel job, you can also specify a minimum number and a
maximum number of processors.
If you specify a maximum and minimum number of processors, the job starts as
soon as the minimum number of processors is available, but it uses up to the
maximum number of processors, depending on how many processors are available
at the time. Once the job starts running, no more processors are allocated to it even
though more may be available later on.
Jobs that request fewer processors than the minimum PROCLIMIT defined for the
queue or application profile to which the job is submitted, or more processors than
the maximum PROCLIMIT are rejected. If the job requests minimum and
maximum processors, the maximum requested cannot be less than the minimum
PROCLIMIT, and the minimum requested cannot be more than the maximum
PROCLIMIT.
If
PARALLEL_SCHED_BY_SLOT=Y in lsb.params, the job specifies a maximum and
minimum number of job slots instead of processors.
Syntax
bsub -n min_proc[,max_proc]
Example
bsub -n 4,16 myjob