NAME

sge_priority - xxQS_NAMExx job priorities

DESCRIPTION

xxQS_NAMExx provide means for controlling job dispatch and run-time priorities. The dispatch priority indicates the importance of pending jobs compared with each other and determines the order in which xxQS_NAMExx dispatches jobs to queue instances. The run-time priority determines the CPU allocation that the operating system assigns to jobs.

JOBS DISPATCH PRIORITY

A job's dispatch priority is affected by a number of factors:

• the identity of the submitting user

• the project under which the job is submitted (or alternatively, the default project of the submitting user)

• any resources requested by the job

• the job's submit time

• the job's initiation deadline time (if specified)

• the -p priority specified for the job (also known as the POSIX priority "pprio")

The effect of each of these is governed by the overall policy setup, which is split into three top-level contributions. Each of these is configured through the xxqs_name_sxx_sched_conf(5) parameters weight_priority, weight_ticket and weight_urgency. These three parameters control to what degree POSIX priority, ticket policy, and urgency policy are in effect. To facilitate interpretation, the raw priorities ("tckts"/"urg"/"ppri") are normalized ("ntckts"/"nurg"/"npprior") before they are used to calculate job priorities ("prio"). Normalization maps each raw urgency/ticket/priority value into a range between 0 and 1.

npprior = normalized(ppri) 
nurg = normalized(urg) 
ntckts = normalized(tckts)
prio = weight_priority * pprio + weight_urgency * nurg + weight_ticket * ntckts

The higher a job's priority value, the earlier it gets dispatched. The urgency policy defines an urgency value for each job. The urgency value

urg = rrcontr + wtcontr + dlcontr

consists of the resource requirement contribution ("rrcontr"), the waiting time contribution ("wtcontr") and the deadline contribution ("dlcontr").

The resource requirement contribution is adding up all resource requirements of a job into a single numeric value.

rrcontr = Sum over all(hrr)

with an "hrr" for each hard resource request. Depending on the resource type two different methods are used to determine the value to be used for "hrr" here. For numeric type resource requests, the "hrr" represents how much of a resource a job requests (on a per-slot basis for pe jobs) and how "important" this resource is considered in comparison to other resources. This is expressed by the formula:

hrr = rurg * assumed_slot_allocation * request

where the resource's urgency value ("rurg") is as specified under urgency in xxqs_name_sxx_complex(5), the job's assumed_slot_allocation represents the number of slots supposedly assigned to the job, and the per-slot request is that which was specified using the qsub(1) -l option. For string type requests the formula is simply

hrr = "rurg"

and directly assigns the resource urgency value as specified under urgency in xxqs_name_sxx_complex(5).

The waiting time contribution represents a weighted waiting time of the jobs

wtcontr = waiting_time * weight_waiting_time

with the waiting time in seconds and the weight_waiting_time value as specified in xxqs_name_sxx_sched_conf(5).

The deadline contribution has an increasing effect as jobs approach their deadline initiation time (see the -dl option in qsub(1)). It is defined as the quotient of the weight_deadline value from xxqs_name_sxx_sched_conf(5) and the (steadily decreasing) free time in seconds until deadline initiation time

dlcontr = weight_deadline / free_time

or is set to 0 for non-deadline jobs. After the deadline passes, the value is static and equal to weight_deadline.

The ticket policy unites functional, override and share tree policies in the ticket value ("tckts"), as is defined as the sum of the specific ticket values ("ftckt"/"otckt"/"stckt") for each sub-policy (functional, override, share):

tckts = ftckt + otckt + stckt

The ticket policies provide a broad range of means for influencing both job dispatch and runtime priorities on a per job, per user, per project, and per department basis.

JOB RUN-TIME PRIORITY

As default jobs are started with the runtime priority defined in the queue instance where the job is started. This priority is applied at job start only and also not changed if the priority of the queue instance changes later.

The run-time priority can be dynamically adjusted in order to meet the goals set with the ticket policy. Dynamic run-time priority adjustment can be turned off (default) globally using reprioritize_interval in xxqs_name_sxx_sched_conf(5).

Note that urgency and POSIX priorities do NOT affect runtime priority.

SEE ALSO

xxqs_name_sxx_intro(1), xxqs_name_sxx_complex(5), qstat(1), qsub(1), xxqs_name_sxx_sched_conf(5), sge_conf(5)

COPYRIGHT

See xxqs_name_sxx_intro(1) for a full statement of rights and permissions.