
Table 1 Resources managed by PRM
Resource managed | Shares | Cap |
CPU | Yes (for FSS PRM | Yes[LINEBREAK](on |
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| CPUCAPON mode; |
on a
Management algorithm
PRM allocates time slices to FSS PRM groups proportional to their shares. When CPUCAPON mode is enabled, the FSS PRM group is given CPU time regardless of whether the time is needed. With
For PSET PRM groups, PRM allocates entire cores to the group according to the current configuration. CPU capping for PSET PRM groups is a result of the number of cores assigned to the group.
Real memory (private) | Yes | Yes | When the system is paging (real memory is |
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| [LINEBREAK](on a exhausted), if a PRM group is exceeding its | |
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| shares, the Memory Resource Groups (MRG) | |
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| kernel causes the process to page. |
Real memory (shared) | N/A | N/A | The amount of memory requested is set aside for |
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| use as shared memory. |
Standard HP-UX resource allocation
Under standard
Figure 1 HP-UX standard resource allocation
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USER2
How PRM can improve on standard allocation
Unlike the standard scheduler, PRM allows you to set priorities on your processes. The following sections illustrate various ways you can use PRM to improve scheduling.
If multiple users or applications within a PRM group are competing for resources, standard
Balancing resource use between users
Figure 2 shows how PRM can alter standard resource allocation and balance system resource use.
In the following scenario, a service provider wants each customer to have an equal share of the machine. Each customer is assigned to a separate PRM group, which is given resource shares equivalent to 50%. The resource being allocated could be either CPU or memory. This configuration guarantees each PRM group 50% of the resource for any given interval. Thus, Customer2’s process receives 50% of the resource; however, because Customer1’s group contains two processes, each
14 Overview