Number of central processors

The CPs defined to an LP are called logical cores. The total number of initial logical cores for each LP cannot be greater than the number of physical cores installed. CPs can be dedicated to LPs or shared by LPs (sharing LPs).

The number of CPs defined for an LP represents the number of logical cores on which the control program will dispatch work and is determined by several factors as described in Maximum number of central processors. If a logical partition enables SMT, each of these logical processor cores will have two CPUs defined. If the processor type supports SMT (for example zIIPs and IFLs), this creates two CPUs per logical core for the control program dispatch work.

On a z17, you can optionally install one or more Internal Coupling Facility (ICF) features for use by a coupling facility LP. See Coupling facility LPs using dedicated Internal Coupling Facility (ICF) processors.

On a z17, you can optionally install one or more Integrated Facility for Linux® (IFL) features for use by a Linux-Only LP. See Processor considerations for Linux-only LPs

You can also optionally install one or more zIIP feature for use by an LP. The total number of initial logical zIIPs for each LP cannot be greater than the number of physical zIIPs installed.

Use the Customize/Delete Activation Profiles task to open a reset or image profile to define the number of CPs for an LP. The Number of processors field is located on the Processor page for the LP.