CPENABLE

The z/OS® CPENABLE parameter can be used to provide selective enablement for I/O interrupts. On the z17, the best ITR is achieved when the fewest CPs are enabled for I/O interrupts. Selective enablement for I/O and the CPENABLE parameter are described in the z/OS MVS Initialization and Tuning Reference, SA23-1380.

A CPENABLE=SYSTEM setting is recommended to minimize the number of CPs handling I/O interrupts in an LP. A CPENABLE=(0,0) setting, enabling all CPs to handle I/O interrupts, can cause performance degradation for logical partitions and is not recommended.