SLURM Reference Manual for HP XC System Software

Scheduler Types
The system administrator for each machine can configure SLURM to invoke any of several alternative
local job schedulers. You can discover which scheduler SLURM currently invokes on any machine by
executing
scontrol show config | grep SchedulerType
where the returned string will have one of these values:
builtin (default) is a first-in-first-out scheduler. SLURM executes jobs strictly in the order
that they were submitted (for each resource partition). Even if resources become
available to start a specific job, SLURM will wait until no previously submitted job
is pending (which sometimes confuses impatient job submitters).
backfill modifies strict FIFO scheduling to take advantage of resource islands that may appear
as earlier jobs complete. SLURM will start later-submitted jobs out of order if resources
become available and if doing so does not delay the expected execution time of any
earlier-submitted job. You increase your job's chances of benefiting from such backfill
scheduling if you:
(1) specify reasonable time limits (the default is the same time limit for all jobs in
your partition, perhaps much too large), and
(2) avoid requiring or excluding specific nodes by name.
BlueGene/L Note: backfill scheduling never occurs on BlueGene/L because that
machine's unusual and complex architecture thwarts reliably finding left over resource
islands to fill.
wiki uses the Maui Scheduler, with a sophisticated set of internal scheduling algorithms.
This choice can be configured in many ways to optimize job throughput. Details are
posted on a support web site at http://supercluster.org/maui (URL:
http://supercluster.org/maui).
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