Describe and implement use of the Fair Share Scheduler class

Describe and implement use of the Fair Share Scheduler class

You can use the fair share scheduler (FSS) to control the allocation of available CPU resources among zones, based on the importance of the workloads in the zone. This workload importance is expressed by the number of shares of CPU resources that you assign to each zone. Even if you are not using FSS to manage CPU resource allocation between zones, you can set the zone's scheduling-class to use FSS so that you can set shares on projects within the zone.

When you explicitly set the cpu-shares property, the fair share scheduler (FSS) will be used as the scheduling class for that zone. However, the preferred way to use FSS in this case is to set FSS to be the system default scheduling class with the dispadmin command. That way, all zones will benefit from getting a fair share of the system CPU resources. If cpu-shares is not set for a zone, the zone will use the system default scheduling class. The following actions set the scheduling class for a zone:

• In the Solaris 10 8/07 release, you can use the scheduling-class property in zonecfg to set the scheduling class for the zone.
• You can set the scheduling class for a zone through the resource pools facility. If the zone is associated with a pool that has its pool.scheduler property set to a valid scheduling class, then processes running in the zone run in that scheduling class by default. If the cpu-shares rctl is set and FSS has not been set as the scheduling class for the zone through another action, zoneadmd sets the scheduling class to FSS when the zone boots.
• If the scheduling class is not set through any other action, the zone inherits the system default scheduling class.

Note that you can use the priocntl to move running processes into a different scheduling class without changing the default scheduling class and rebooting.

How to Associate a Pool with a Scheduling Class

You can associate a pool with a scheduling class so that all processes bound to the pool use this scheduler. To do this, set the pool.scheduler property to the name of the scheduler. This
example associates the pool pool_batch with the fair share scheduler (FSS).

1.      Become superuser, or assume a role that includes the Process Management profile.

2.      Modify pool pool_batch to be associated with the FSS.

# poolcfg -c 'modify pool pool_batch (string pool.scheduler="FSS")'

3.      Display the edited configuration.

# poolcfg -c info system tester         string  system.comment         int     system.version 1         boolean system.bind-default true         int     system.poold.pid 177916           pool pool_default                 int     pool.sys_id 0                 boolean pool.active true                 boolean pool.default true                 int     pool.importance 1                 string  pool.comment                 pset    pset_default           pset pset_default                 int     pset.sys_id -1                 boolean pset.default true                 uint    pset.min 1                 uint    pset.max 65536                 string  pset.units population                 uint    pset.load 10                 uint    pset.size 4                 string  pset.comment                 boolean testnullchanged true                   cpu                         int     cpu.sys_id 3                         string  cpu.comment                         string  cpu.status on-line                   cpu                         int     cpu.sys_id 2                         string  cpu.comment                         string  cpu.status on-line                   cpu                         int     cpu.sys_id 1                         string  cpu.comment                         string  cpu.status on-line                   cpu                         int     cpu.sys_id 0                         string  cpu.comment                         string  cpu.status on-line           pool pool_batch                 boolean pool.default false                 boolean pool.active true                 int pool.importance 1                 string pool.comment                 string pool.scheduler FSS                 pset batch           pset pset_batch                 int pset.sys_id -2                 string pset.units population                 boolean pset.default true                 uint pset.max 10                 uint pset.min 2                 string pset.comment                 boolean pset.escapable false                 uint pset.load 0                 uint pset.size 0                   cpu                         int     cpu.sys_id 5                         string  cpu.comment                         string  cpu.status on-line                   cpu                         int     cpu.sys_id 4                         string  cpu.comment                         string  cpu.status on-line

4.      Commit the configuration at /etc/pooladm.conf:

# pooladm -c

5.      (Optional) To copy the dynamic configuration to a static configuration file called /tmp/backup, type the following:

# pooladm -s /tmp/backup