Scheduling Class in a Zone

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 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:

• 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. See Introduction to Resource Pools and How to Associate a Pool With a Scheduling Class.

• 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 described in the priocntl(1) man page to move running processes into a different scheduling class without changing the default scheduling class and rebooting.