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:

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.

	NOTE: On a vPars system, when a virtual partition goes down and contains a deconfigured or deactivated CPU, the Monitor will try to decommission the CPU from use and replace it with another good CPU if possible. If this is not possible, the vPars Monitor will not allow the partition to boot until the deconfigured or deactivated CPU can be taken out of use. Following are some cases where the vPars Monitor may not allow the virtual partition to boot: There is a deconfigured or deactivated CPU which has been reserved for the partition as part of the total (cpu::num) request and vPars Monitor does not have any free CPUs with which to replace it. To correct this, you can delete CPUs from other partitions or from this partition. There is a deconfigured or deactivated CPU that has been bound to the partition by hardware path (cpu:hw_path) which the vPars Monitor is not able to replace with another available CPU. To correct this, you can remove the CPU specified by hardware path using -d cpu:hw_path to allow the deconfigured or deactivated CPU to be decommissioned and replaced with another (working) CPU. There is a deconfigured CPU which has been reserved for the partition as part of a CLP request (cell:cell_ID:cpu::num) and there are no free CLPs in that cell. To correct this, you can make available CPUs from that cell by deleting the CPUs that are part of this cell from other partitions or delete the CPUs from the cell in this partition. Dual-core processors have two CPUs (that is, cores) per processor. Deactivation happens on a CPU level, but deconfiguration happens at the socket level. If a processor’s socket is deconfigured, both CPUs sharing the socket will be unavailable. (Integrity only) If a CPU is marked for deconfiguration using an EFI command and the nPartition is not rebooted (for example, the vPars Monitor is immediately booted), the vPars Monitor will not know or indicate (including with vparstatus) that the CPU has been marked for deconfiguration and will use the CPU like any other working CPU.