HP-UX Virtual Partitions Administrator Guide (includes A.05.09) (5900-2188, March 2012)

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 on the BSC website at
http://www.hp.com/go/bizsupport or see 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.
CPU: CPU Monitor (Formerly Known As LPMC Monitor)
The CPU Monitor (a part of the diagnostic tool Event Monitor Services (EMS) and not a part of the
vPars Monitor) is designed to monitor cache parity errors within the CPUs on the system. With its
Dynamic Processor Resilience (DPR), if the CPU Monitor detects a pre-determined number of errors,
the CPU Monitor will deactivate a CPU for the current boot session. If the problems are severe
enough, the CPU Monitor will deconfigure the socket for the next boot of the system.
Deactivation of a CPU means that the OS will attempt to no longer use the CPU by migrating all
threads off the CPU. Deactivation of a CPU is not persistent across an OS or system reboot.
Deconfiguration of a socket means that the EMS issues a firmware call, marking the socket for
deconfiguration on the next system boot. On the next system boot, none of the cores in the target
socket are visible to either the OS in standalone mode or the OS instances of the virtual partitions.
The deconfiguration is persistent across system boots.
Note the following two items:
• A deactivation of a CPU does not mean a deconfiguration of its socket. The CPU Monitor is
able to determine whether the CPU needs to be deactivated or whether it needs to take further
action and deconfigure the socket.
• A reboot of a virtual partition is not the same as a reboot of the system (the entire box or
nPartition).
The exceptions to the deactivation of CPUs are the boot processor of each OS instance (the boot
processor has a logical instance of zero) and the last CPU in a cell or nPartition. The exception to
the deconfiguration of sockets is that the last remaining socket will not be deconfigured (otherwise,
the system could not boot).
If any spare iCAP (formerly known as iCOD) or PPU CPUs are available, the necessary number of
CPUs will be activated to replace the CPUs deactivated.
CPU: CPU Monitor (Formerly Known As LPMC Monitor) 195