Central Processors - IBM z13s Technical Manual

An IFL pool of two IFLs
A zIIP pool of five zIIPs
PUs are placed in the pools in the following circumstances:
When the system undergoes POR
At the time of a concurrent upgrade
As a result of the addition of PUs during a CBU
Following a capacity on-demand upgrade through On/Off CoD or CIU
PUs are removed from their pools when a concurrent downgrade takes place as the result of
the removal of a CBU. They are also removed through On/Off CoD process and the
conversion of a PU. When a dedicated LPAR is activated, its PUs are taken from the correct
pools. This is also the case when an LPAR logically configures a PU on, if the width of the
pool allows for it.
For an LPAR, logical PUs are dispatched from the supporting pool only. The logical CPs are
dispatched from the CP pool, logical zIIPs from the zIIP pool, logical IFLs from the IFL pool,
and the logical ICFs from the ICF pool.
PU weighting
Because CPs, zIIPs, IFLs, and ICFs have their own pools from where they are dispatched,
they can be given their own weights. For more information about PU pools and processing
weights, see the z Systems Processor Resource/Systems Manager Planning Guide,
SB10-7162.

3.5.2 Central processors

A central processor (CP) is a PU that uses the full z/Architecture instruction set. It can run
z/Architecture-based operating systems (z/OS, z/VM, TPF, z/TPF, z/VSE, and Linux), the
Coupling Facility Control Code (CFCC), and IBM zAware. Up to 6 PUs can be characterized
as CPs, depending on the configuration.
z13s servers can be initialized either in LPAR mode or in Elastic PR/SM mode. For more
information, see Appendix E, "IBM Dynamic Partition Manager" on page 501. CPs are
defined as either dedicated or shared. Reserved CPs can be defined to an LPAR to allow for
nondisruptive image upgrades. If the operating system in the LPAR supports the logical
processor add function, reserved processors are no longer needed. Regardless of the
installed model, an LPAR can have up to 141 logical processors defined (the sum of active
and reserved logical processors). In practice, define no more CPs than the operating system
supports. For example, the z/OS V1R13 LPAR supports a maximum of 100 logical CPs and
z/OS V2R1 LPAR supports a maximum of 141 logical CPs. See the z Systems Processor
Resource/Systems Manager Planning Guide, SB10-7162.
All PUs that are characterized as CPs within a configuration are grouped into the CP pool.
The CP pool can be seen on the HMC workplace. Any z/Architecture operating systems,
CFCCs, and IBM zAware can run on CPs that are assigned from the CP pool.
z13s servers have 26 capacity levels, which are named from A to Z. Within each capacity
level, a one, two, three, four, five, or six-way model is offered. Each model is identified by its
capacity level indicator (A through Z) followed by an indication of the number of CPs available
(01 - 06). Therefore, z13s servers offer 156 capacity settings. All models have a related
millions of service units (MSU) value that is used to determine the software license charge for
monthly license charge (MLC) software (see Table 2-12 on page 73).
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IBM z13s Technical Guide