HP-UX Workload Manager User's Guide

WLM quick start: the essentials for using WLM
How to put an application under WLM control
Chapter 2 81
— Whole-core: HP-UX processor sets (PSETs)
— Sub-core: Fair Share Scheduler (FSS) groups
To have resources migrated among workloads as needed, you create one
or more SLOs for each workload. (In the case of nPartitions, which
represent hardware, the core movement is simulated using Instant
Capacity to deactivate one or more cores in one nPartition and then
activate cores in another nPartition.) In defining an SLO, you specify the
SLO’s priority. You can also specify a usage goal to attain a targeted
resource usage. Or, if a performance measure (metric) is available, you
can specify a metric goal. As the applications run, WLM compares the
application usage or metrics against the goals. To achieve the goals,
WLM automatically adjusts CPU allocations for the workloads.
For workload groups (which share the resources of a single HP-UX
instance), WLM can manage each group’s real memory and disk
bandwidth resources in addition to its CPU allocation.
NOTE WLM adjusts only a workload group’s CPU allocation in response to SLO
performance. Thus, WLM SLO management is most effective for
workloads that are CPU-bound.
How to put an application under WLM control
This section applies only to workloads that divide PRM-based resources
within a single HP-UX instance. If you are not going to use WLM in this
way, you can skip the rest of this section and go to “How to determine a
goal for your workload” on page 87.
WLM can treat an nPartition or virtual partition as a workload. The
workload consists of all the processes running in the operating system
instance on the partition. WLM also allows you to divide the resources of
a single operating system into PSETs or FSS groups. When dividing the
resources of a single operating system, the workloads are known as
workload groups.
When a system is divided into workload groups, each application must go
into a workload group. By default, processes run by root go into the
PRM_SYS group, and processes run by nonroot users go into the OTHERS