Sun Microsystems manual 108

Version 3.1-enSolaris 10 Container Guide - 3.1 5. Cookbooks Effective: 30/11/2009

5.5.4. Fair share scheduler

[ug] The ratio of CPU usage between zones or projects can be set.

This is implemented by he so-called fair share scheduler. CPU shares are allocated as follows:

∙For zones, by using add rctl and the attribute zone.cpu-sharesin the zonecfg command.

∙For projects, this is set in the project database (/etc/project, or NIS or LDAP) and the attribute project.cpu-shares(global and/or local zone).

∙The zones/projects must be allocated to the same resource pool.

∙In the resource pool, the fair share scheduler must be activated.

∙In the global zone, the resource pool can also be limited to a subset of processors in the system.

The operating system provides for fairness, if the CPUs of the resource pool are used to capacity. The allocated shares of the projects and the zones with active processes are used to calculate the nominal value for CPU usage. The nominal value of CPU usage is calculated with the formula: (zone shares) * (number of CPUs) / (sum of the shares of the active zones).

If the CPU usage approaches 100% and the amount of consumed CPU time is larger than the nominal value, the fair share scheduler takes countermeasures by reducing priority.

Furthermore:

∙The settings for CPU shares can be dynamically set with the command prctl.

∙The affiliation of a zone with a resource pool can be changed at any time with the command poolbind.

If CPU usage in a resource pool is noticeably smaller than 100%, the fair share scheduler does not control CPU usage. In this situation, a zone in the resource pool can use more than it is actually entitled to. If this is not desired, additional limitation with processor sets or cpu capping is recommended.

5.5.5. Static CPU resource management between zones

[ug] Static resource management between zones determines how resources should be distributed in a normal case following a booting routine:

∙To create a resource pool, the commands poolcfg and pooladm are used.

∙The affiliation of a zone to a resource pool for zonecfg can be set with the attribute pool.

∙The settings for fairness between the zones are adjusted with add rctl in zonecfg. We recommend setting zone.cpu-shares(CPU share) and additionally zone.max-lwps(maximum number of threads).

5.5.6. Dynamic CPU resource management between zones

[ug] This refers to commands that allow the user to reset resource controls while the zones are running in order to react to a temporary load situation.

The commands prctl and poolbind are used. If necessary, new resource pools can temporarily be created with poolcfg and pooladm to separate loads.

5.5.7. Static CPU resource management in a zone

[ug] The ratio of CPU usage between applications in a zone can be adjusted as well.

This is done with the definition of resource pools within the zone and use of the fair share scheduler with projects inside of the zone. Allocation of CPUs to resource pools is not possible within the zone.

∙The allocation of applications to projects is done by configuration in the files /etc/project and /etc/user_attr .

∙In /etc/project, it can be defined which resource pool a project should run in.

∙To create a resource pool in the zone, the commands poolcfg and pooladm are used. However, processors cannot be assigned.

∙In the resource pool, the fair share scheduler (FSS) must be activated.

5.5.8. Dynamic CPU resource management in a zone

[ug] This refers to commands used to reset the resource controls within the zone while running, in order to react to a temporary load situation.

The commands prctl and poolbind can be used to change share values of projects or associations of project to resource pools. If necessary, new resource pools can temporarily be

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