Specifications

Chapter 3. Virtualization 131
The Power 780 allows up to 96 cores in a single system, supporting the following maximums:
򐂰 Up to 96 dedicated partitions
򐂰 Up to 960 micro-partitions (10 micro-partitions per physical active core)
An important point is that the maximums stated are supported by the hardware, but the
practical limits depend on application workload demands.
Additional information about virtual processors includes:
򐂰 A virtual processor can be running (dispatched) either on a physical processor or as
standby waiting for a physical processor to became available.
򐂰 Virtual processors do not introduce any additional abstraction level. They are only a
dispatch entity. When running on a physical processor, virtual processors run at the same
speed as the physical processor.
򐂰 Each partition’s profile defines CPU entitlement that determines how much processing
power any given partition should receive. The total sum of CPU entitlement of all partitions
cannot exceed the number of available physical processors in a Shared Processor Pool.
򐂰 The number of virtual processors can be changed dynamically through a dynamic
LPAR operation.
Processing mode
When you create a logical partition you can assign entire processors for dedicated use, or you
can assign partial processing units from a Shared Processor Pool. This setting defines the
processing mode of the logical partition. Figure 3-7 shows a diagram of the concepts
discussed in this section.
Figure 3-7 Logical partitioning concepts
Set of micro-partitions
KEY:
vp Virtual processor
lp Logical processor
PrU Processing Units
Shared-Processor Pool 0
Set of micro-partitions
Shared-Processor Pool 1
lp lp lp lp lp lp lp lp lp lp lp lp
AIX V6.1
1.5 PrU
AIX V5.3
0.5 PrU
AIX V6.1
1.5 PrU
Linux
0.5 PrU
vpvp vp vpvp vp
lp lp lp lp lp lp
AIX V5.3
AIX V6.1
Dedicated processors Dedicated processors
POWER Hypervisor
8-core SMP System