HP Process Resource Manager User's Guide

Understanding how PRM manages resources
How PRM controls resources
Chapter 236
Applications and users that are assigned to a PSET PRM group have
dedicated CPU cycles from the cores assigned to the group. Competition
for CPU cycles within the processor set are handled using the HP-UX
time-share scheduler.
Table 2-1 shows a 16-core system that has four FSS PRM groups defined
within the default PSET, and two additional
system-administrator-defined PSET PRM groups. The default PSET
contains eight cores, one of which is core 0. This is the only core that is
required to be in the default PSET. The remaining cores in the default
PSET are used by the PRM_SYS, OTHERS, Dev, Appl FSS PRM groups.
There are two databases on this system that each have four cores
assigned to them. Unlike the cores in the default PSET, the cores in the
database PSET PRM groups are dedicated cores using the HP-UX
time-share scheduler. This creates isolated areas for the databases.
What are shares?
Resource shares are the minimum amounts of a resource assigned to
each PRM group in a PRM configuration file (default name /etc/prmconf).
For FSS PRM groups, you can assign CPU, disk bandwidth, and real
memory shares, although only CPU share assignments are required. For
PSET PRM groups, you can only assign real memory in shares. For both
types of groups, you can also specify shared memory allocations.
In addition to minimum amounts, you can specify maximum amounts of
of some resources that PRM groups can use. For FSS PRM groups, you
can specify maximum amounts of CPU and memory resources. For PSET
PRM groups, you can assign a maximum amount of memory; however,
Table 2-1 Processor sets example
PRM Group
Type
Group Name Core ID Use
FSS PRM
groups
(Default PSET)
PRM_SYS,
OTHERS, Dev,
Appl
0, 1, 4, 5, 8, 9
12, 13
System
processes,
general users,
and developers
PSET PRM
group
SalesDB 2, 3, 6, 7 Sales database
PSET PRM
group
FinanceDB 10, 11, 14, 15 Financial
database