LSF Version 7.3 - Using Platform LSF HPC

After the job finishes, LSF destroys the pset. If no host meets the CPU requirements,
the job remains pending until processors become available to allocate the pset.
CPU 0 in the default pset 0 is always considered last for a job, and cannot be taken out
of pset 0, since all system processes are running on it. LSF cannot create a pset with CPU
0; it only uses the default pset if it cannot create a pset without CPU 0.
RLA runs on each HP-UX11i host. It is started and monitored by sbatchd. RLA
provides services for external clients, including pset scheduler plugin and
sbatchd to:
◆ Allocate and deallocate job psets
◆ Get the job pset ID
◆ Suspend a pset when job is suspended, and reassign all CPUs within pset back to
pset 0
◆ Resume a pset, and before a job is resumed, assign all original CPUs back to the job
pset
◆ Get pset topology information, cells, CPUs, and processor distance between cells.
◆ Get updated free CPU map
◆ Get job resource map
RLA maintains a status file in the directory defined by LSB_RLA_WORKDIR in
lsf.conf, which keeps track of job pset allocation information. When RLA starts, it
reads the status file and recovers the current status.
Assumptions and limitations
User-level account and system account mapping are not supported. If a user account
does not exist on the remote host, LSF cannot create a pset for it.
By default, job start time is not accurately predicted for pset jobs with topology options,
so the forecast start time shown by
bjobs -l is optimistic. LSF may incorrectly
indicate that the job can start at a certain time, when it actually cannot start until some
time after the indicated time.
For a more accuration start-time estimate, you should configure time-based slot
reservation. With time-based reservation, a set of pending jobs will get future allocation
and estimated start time.
See Administering Platform LSF for more information about time-based slot
reservation.
Jobs submitted to a chunk job queue are not chunked together, but run outside of a pset
as a normal LSF job.
◆ When LSF selects pset jobs to preempt, specialized preemption preferences, such
as MINI_JOB and LEAST_RUN_TIME in the PREEMPT_FOR parameter in
lsb.params, and others are ignored when slot preemption is required.
◆ Preemptable queue preference is not supported.
When a job is suspended with bstop, all CPUs in the pset are released and reassigned
back to the default pset (pset 0). Before resuming the job LSF reallocates the pset and
rebinds all job processes to the job pset.
Job pre-execution programs run within the job pset, since they are part of the job. Post-
execution programs run outside of the job pset.