Administering Platform LSF - SAS

Suspending Conditions
Suspending Conditions
LSF provides different alternatives for configuring suspending conditions.
Suspending conditions are configured at the host level as load thresholds,
whereas suspending conditions are configured at the queue level as either load
thresholds, or by using the STOP_COND parameter in the lsb.queues file, or
both.
The load indices most commonly used for suspending conditions are the CPU
run queue lengths (r15s, r1m, and r15m), paging rate (pg), and idle time (it).
The (swp) and (tmp) indices are also considered for suspending jobs.
To give priority to interactive users, set the suspending threshold on the it
(idle time) load index to a non-zero value. Jobs are stopped when any user is
active, and resumed when the host has been idle for the time given in the it
scheduling condition.
To tune the suspending threshold for paging rate, it is desirable to know the
behaviour of your application. On an otherwise idle machine, check the
paging rate using lsload, and then start your application. Watch the paging
rate as the application runs. By subtracting the active paging rate from the idle
paging rate, you get a number for the paging rate of your application. The
suspending threshold should allow at least 1.5 times that amount. A job can be
scheduled at any paging rate up to the scheduling threshold, so the suspending
threshold should be at least the scheduling threshold plus 1.5 times the
application paging rate. This prevents the system from scheduling a job and
then immediately suspending it because of its own paging.
The effective CPU run queue length condition should be configured like the
paging rate. For CPU-intensive sequential jobs, the effective run queue length
indices increase by approximately one for each job. For jobs that use more than
one process, you should make some test runs to determine your job’s effect on
the run queue length indices. Again, the suspending threshold should be equal
to at least the scheduling threshold plus 1.5 times the load for one job.
Configuring load thresholds at queue level
Syntax
The queue definition (lsb.queues) can contain thresholds for 0 or more of
the load indices. Any load index that does not have a configured threshold has
no effect on job scheduling.
Each load index is configured on a separate line with the format:
load_index = loadSched/loadStop
Specify the name of the load index, for example r1m for the 1-minute CPU run
queue length or pg for the paging rate. loadSched is the scheduling threshold
for this load index. loadStop is the suspending threshold. The loadSched
condition must be satisfied by a host before a job is dispatched to it and also
before a job suspended on a host can be resumed. If the loadStop condition
is satisfied, a job is suspended.
The loadSched and loadStop thresholds permit the specification of
conditions using simple AND/OR logic. For example, the specification:
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Administering Platform LSF