NAME
sge_priority - Sun Grid Engine job priorities
DESCRIPTION
Sun Grid Engine 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 Sun
Grid Engine 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:
o the identity of the submitting user
o the project under which the job is submitted (or alternatively, the
default project of the submitting user)
o any resources requested by the job
o the job's submit time
o the job's initiation deadline time (if specified)
o 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 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 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 -l qsub(1) option. For
string type requests the formula is simply
hrr = "rurg"
and directly assigns the resource urgency value as specified under
urgency in complex(5).
The waiting time contribution represents a weighted weighting 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 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 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. See the Sun Grid Engine Installation
and Administration Guide for details.
JOB RUN-TIME PRIORITY
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
sched_conf(5) If no dynamic run-time priority adjustment is done at a
host level, the priority specification in queue_conf(5) is in effect.
Note that urgency and POSIX priorities do NOT affect runtime priority.
SEE ALSO
sge_intro(1), complex(5), qstat(1), qsub(1), sched_conf(5), sge_conf(5)
Sun Grid Engine Installation and Administration Guide
COPYRIGHT
See sge_intro(1) for a full statement of rights and permissions.