LSF Version 7.3 - Administering Platform LSF

Administering Platform LSF 321
Fairshare Scheduling
Committed run time weighting factor
Committed run time is the run time requested at job submission with the -W option
of
bsub, or in the queue configuration with the RUNLIMIT parameter. By default,
committed run time does not affect the dynamic priority.
While the job is running, the actual run time is subtracted from the committed run
time. The user’s dynamic priority decreases immediately to its lowest expected
value, and is maintained at that value until the job finishes. Job run time is
accumulated as usual, and historical run time, if any, is decayed.
When the job finishes, the committed run time is set to zero and the actual run time
is added to the historical run time for future use. The dynamic priority increases
gradually until it reaches its maximum value.
Providing a weighting factor in the run time portion of the dynamic priority
calculation prevents a “job dispatching burst” where one user monopolizes job slots
because of the latency in computing run time.
Configure
committed run
time
1 Set a value for the COMMITTED_RUN_TIME_FACTOR parameter in
lsb.params. You should also specify a RUN_TIME_FACTOR, to prevent the
user’s dynamic priority from increasing as the run time increases.
If you have also enabled the use of historical run time, the dynamic priority is
calculated according to the following formula:
dynamic priority = number_shares / (cpu_time * CPU_TIME_FACTOR +
(historical_run_time + run_time) * RUN_TIME_FACTOR +
(committed_run_time - run_time) * COMMITTED_RUN_TIME_FACTOR +
(1 + job_slots) * RUN_JOB_FACTOR)
committed_run_time—The run time requested at job submission with the
-W
option of
bsub, or in the queue configuration with the RUNLIMIT parameter.
This calculation measures the committed run time in hours.
In the calculation of a user’s dynamic priority,
COMMITTED_RUN_TIME_FACTOR determines the relative importance of
the committed run time in the calculation. If the
-W option of bsub is not
specified at job submission and a RUNLIMIT has not been set for the queue,
the committed run time is not considered.
COMMITTED_RUN_TIME_FACTOR can be any positive value between 0.0
and 1.0. The default value is 0.0. As the value of
COMMITTED_RUN_TIME_FACTOR approaches 1.0, more weight is given
to the committed run time in the calculation of the dynamic priority.
Limitation If you use queue-level fairshare, and a running job has a committed run time, you
should not switch that job to or from a fairshare queue (using
bswitch). The
fairshare calculations will not be correct.
Run time displayed
by bqueues and
bhpart
The run time displayed by bqueues and bhpart is the sum of the actual,
accumulated run time and the historical run time, but does not include the
committed run time.