Hi,
I have a POWER8 server running in Processor Implementation Mode: POWER 7.
I have 2 LPAR's, both are capped with 4 cores.
One of them displays:
Shared-SMT-4
and the other:
Dedicated-SMT-4
What is the difference when running in capped mode?
Thanks
When running in Dedicated Processor mode - that parition may donate unused cycles to the shared pool. However, when using it's processors CPU1 will always be the exact same physical core, idem for the other three - whatever is assigned when it is activated is what they will be.
When running is Shared Mode only the number of virtual cores is defined. On a system with, e.g., 16 cores activated - while the PHYP will attempt to map virtual to the same physical core (aka Home node) - it is not a requirement - hence the physical core assigned may change (e.g., another LPAR is using it, so rather than wait for it to be free a different core is assigned)
p.s. When donating a core - if a dedicated (processor) partition wants it CPU the borrowing LPAR gets removed immediately by the PHYP.
Hope this explains the basics!