HP Process Resource Manager (PRM) manual Resource allocation, What are processor sets?, Dev, Appl

Resource allocation

Resources are allocated to PRM groups differently depending on the resource and the type of PRM group. For FSS PRM groups, resources are typically allocated in shares. For PSET PRM groups, you allocate CPU resources using processor sets. Real memory resources are allocated in shares (private memory) or megabytes (shared memory).

What are processor sets?

Processor sets allow cores on your system to be grouped together in a set by the system administrator and assigned to a PSET PRM group. Once these cores are assigned to a PSET PRM group, they are reserved for use by the applications and users assigned to that group. Using processor sets allows the system administrator to isolate applications and users that are CPU-intensive, or that need dedicated on-demand CPU resources.

How processor sets work?

Processor sets are a way of allocating dedicated CPU resources to designated applications and users. At system initialization time, a default PSET is created. This default PSET initially consists of all of your system’s cores. All FSS PRM group CPU allocation occurs in the default PSET. The system administrator can create additional PSET PRM groups and assign cores, applications, and users to those groups. Once cores are assigned to a PSET PRM group, they cannot be used by another group until a new configuration is loaded.

NOTE: When you have PRM groups based on PSETs enabled:

•Do not modify the PSETs manually using the psrset command

•Do not adjust CPU counts in virtual partitions using the vparmodify command

•Do not adjust Instant Capacity (iCAP), Temporary Instant Capacity (TiCAP), or Pay Per Use resources using the icapmodify or ppuconfig commands

•Do not perform online cell operations, using parolrad or any other interface, while PRM is managing the system (For more information, see the WARNINGS section in the prmconfig(1) manpage.)

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 (page 18) 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.

Table 2 Processor sets example

PRM Group Type	Group Name	Core ID	Use
FSS PRM groups (Default	PRM_SYS, OTHERS,	0, 1, 4, 5, 8, 9 12, 13	System processes, general
PSET)	Dev, Appl		users, and developers
PSET PRM group	SalesDB	2, 3, 6, 7	Sales database
PSET PRM group	FinanceDB	10, 11, 14, 15	Financial database

18 Understanding how PRM manages resources