Guardian Procedure Calls Reference Manual

Returned Value
INT
A file system error code that indicates the outcome of the call:
FEOK0
The procedure executed successfully.
FEBOUNDSERR22
An invalid address was specified for the previousControlFlags parameter.
FESECVIOL48
The caller does not have the necessary permissions.
See Considerations below for details.
FEBADOP564
Invalid controlFlagsMask bits were set.
FEBADPARMVALUE590
An invalid or down CPU was specified.
Considerations
CAUTION: Changing these control settings can severely restrict the ability of the process scheduler
to dynamically balance the workload of the CPU or improve its responsiveness. This can result in
performance problems if the workload and performance characteristics of the affected processes
are not well understood in the context of the overall customer workload. See the Guardian
Programmer's Guide for additional guidelines on the use of this interface.
• The security requirements of this interface are that the caller must be locally logged on in the
super group (super.*) when calling IPUAFFINITY_CONTROL_ with a nonzero
controlFlagsMask. There are no security restrictions on the caller when a zero
controlFlagsMask is specified, indicating that the caller wants to just get the current control
settings.
• Setting bit 63 to 1 in the controlFlagsMask and controlFlagsSetting may have a
performance impact if called when there are many processes in the specified CPU(s) with IPU
associations established. To avoid this impact it is recommended to first use the
IPUAFFINITY_SET_ procedure to remove the IPU associations for all individual processes whose
IPU assignment has been set via that procedure.
• The IPU affinity control settings do not persist beyond the life of a CPU. Settings must be
re-established after a CPU reload.
• This procedure can result in the ZNSK-EVT-PS-CHANGE EMS event being generated. See the
description of this event in the HP NonStop Operating System Event Management Programming
Manual for details.
738 Guardian Procedure Calls (H-K)