HP-UX Virtual Partitions Administrator's Guide (includes A.05.02)

CPU, Memory, and I/O Resources (A.05.xx)
CPUs: Managing I/O Interrupts
Chapter 6
230
CPUs: Managing I/O Interrupts
This section describes information you need if you are managing I/O interrupts on a vPars-enabled system.
Note that migrating interrupts should only be done by advanced administrators for performance tuning.
intctl command
The intctl command is a HP-UX tool that allows you to manage I/O interrupts among active CPUs.
For HP-UX 11i v2 and later, the software for intctl is part of the Core OS.
For more information, see the Interrupt Migration Product Note available at http://docs.hp.com or the intctl
(1M) manpage.
Notes
• At boot time of a virtual partition, interrupts are processed by all the CPUs in the virtual partition.
• After boot, CPUs that are added to the virtual partition are not assigned to process I/O interrupts.
However, you can migrate I/O interrupts to any added CPU using intctl.
• After boot, CPUs that are deleted from a virtual partition no longer process I/O interrupts for the
partition. When a CPU is deleted from a virtual partition, if the deleted CPU has I/O interrupts, the I/O
interrupts are automatically and transparently reassigned to other active CPUs in the partition.
NOTE Repeatedly adding and deleting CPUs without a reboot of the target virtual partition may
cause an imbalance in the interrupt processing load across the CPUs of the virtual partition.
However, you can use intctl to rectify the imbalance if necessary.