Chapter 3. Virtualization 127
Micropartitions are created and then identified as members of either the default shared
processor pool
0
or a user-defined shared processor pool
n
. The virtual processors that exist
within the set of micropartitions are monitored by the POWER Hypervisor, and processor
capacity is managed according to user-defined attributes.
If the Power Systems server is under heavy load, each micropartition within a shared
processor pool is guaranteed its processor entitlement plus any capacity that it might be
allocated from the reserved pool capacity if the micropartition is uncapped.
If certain micropartitions in a shared processor pool do not use their capacity entitlement, the
unused capacity is ceded and other uncapped micropartitions within the same shared
processor pool are allocated the additional capacity according to their uncapped weighting. In
this way, the entitled pool capacity of a shared processor pool is distributed to the set of
micropartitions within that shared processor pool.
All Power Systems servers that support the multiple shared processor pools capability have a
minimum of one (the default) shared processor pool and up to a maximum of 64 shared
processor pools.
Default shared processor pool (SPP
0
)
On any Power Systems server supporting multiple shared processor pools, a default shared
processor pool is always automatically defined. The default shared processor pool has a pool
identifier of zero (SPP ID = 0) and can also be referred to as SPP
0
. The default shared
processor pool has the same attributes as a user-defined shared processor pool except that
these attributes are not directly under the control of the system administrator. They have fixed
values (Table 3-4).
Table 3-4 Attribute values for the default shared processor pool (SPP
0
)
Creating multiple shared processor pools
The default shared processor pool (SPP
0
) is automatically activated by the system and is
always present.
All other shared processor pools exist, but by default are inactive. By changing the maximum
pool capacity of a shared processor pool to a value greater than zero, it becomes active and
can accept micropartitions (either transferred from SPP
0
or newly created).
SPP
0
attribute Value
Shared processor pool ID 0
Maximum pool capacity The value is equal to the capacity in the physical shared
processor pool.
Reserved pool capacity 0
Entitled pool capacity Sum (total) of the entitled capacities of the micropartitions in the
default shared processor pool.
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