HP-UX Workload Manager User's Guide

Integration with other products
Integrating with processor sets (PSETs)
Appendix D 405
Integrating with processor sets (PSETs)
PSETs allow you to group processors together, dedicating those CPU
resources to certain applications. WLM can automatically adjust the
number of CPU resources in a PSET-based workload group in response to
SLO performance. Combining PSETs and WLM, you can dedicate CPU
resources to a group without fear of the group’s needing additional CPU
resources when activity peaks or concern that the group, when less busy,
has resources that other groups could be using.
For information on configuring integration with PSETs, see the section
“Specifying workload groups (optional)” on page 159.
WLM supports the Hyper-Threading feature for PSET-based groups.
Cores can be moved from one partition to another and will take on the
Hyper-Threading state (enabled or disabled) of their destination PSET.
When new PSETs are created, they inherit the state of the system unless
specified otherwise. You can override the default state by explicitly
enabling or disabling Hyper-Threading for any cores assigned to a
specific PSET-based group. To explicitly enable or disable
Hyper-Threading for a PSET-based group, specify the LCPU keyword
with the PSET group definition in the prm structure. For information on
setting the Hyper-Threading state for a specific WLM PSET-based group,
see “Specifying workload groups (optional)” on page 159.
The PRM configuration generated by the WLM configuration file reflects
the per-PSET Hyper-Threading state currently specified for the affected
workload groups.
The LCPU keyword is based on an attribute value that can also be
examined and set with psrset -t. For more information, see psrset(1M).
You can modify the Hyper-Threading state of the system by using the
kctune command; for more information, see kctune(1M).
NOTE When WLM is managing PSETs, do not use the psrset or kctune
command to change PSET settings (including the Hyper-Threading state
of the system or the Hyper-Threading state set for any PSET). Stop
WLM before using these commands to modify PSETs. Whenever
possible, use WLM to control PSETs.