Technical data

Processor Sets (Psets) on nPartitions
Introduction to Psets
HP System Partitions Guide: Administration for nPartitions—rp7410
EMSP—[e-mail]
330
Introduction to Psets
HP’s processor set (Pset) product is an optional software package that
runs on any HP-UX 11i system, including all nPartition servers. The
Pset software package is free and is available from the
http://software.hp.com Web site.
Each processor set (Pset) is a group of active processors that functions as
an independent scheduling allocation domain. When the Pset software is
installed, you can establish multiple Psets in a single HP-UX system.
By dividing the active processors in an nPar into multiple Psets, you can
provide processor resource isolation for applications that run in each
Pset. Each application only has access to the processors assigned to the
Pset in which it runs.
You can dynamically create and reconfigure Psets using the psrset
command or HP’s Process Resource Manager (PRM). You also can launch
each thread or process to run in a specific Pset and can manually migrate
threads and processes to different Psets while they run.
Thread and
Process Pset
Bindings
In systems where Pset software is installed, every thread and process is
bound to only one Pset at a time.
Applications are not migrated to different Psets unless you have
configured PRM to do so, or if you manually bind a process to a different
Pset using the psrset command.
HP-UX load balancing occurs within each Pset. Because load balancing
does not occur across Psets, processors in one Pset can potentially be
oversubscribed while processors in another Pset are nearly idle. This is
an aspect of the processor resource isolation that Psets provide.
Both real-time and time-share schedulers are supported for processor
sets and each Pset has its own schedulers. So, for example, real-time
processes in one Pset only contend for processors in the Pset in which
they are running.
Use of the HP-UX gang scheduler is supported only in the default Pset
(processor set ID 0), as of the current Pset software release. See the
gang_sched (7) manpage or the mpsched (1) manpage for details on using
gang scheduling.
HP Restricted / DRAFT
DRAFT NOV 2001