>My understanding is a Task (TCB) in an address spaces always requires a CPU to >be assigned/associated with.
Yes. > So with Logical/Virtual CPUS, can I have more TCBS, actively dispatched at > the same time in the same Address Space, than the Physical CPUs ? No. A single physical CP can only execute the instructions of a single TCB (or SRB) at any time. No matter how many logical CPs you assign to an LPAR, the number of physical CPs in your machine limit the number of units of work that can run in parallel, i.e. at the same time. When you define more than one LPAR on your machine, the total number of logical CPs of all LPARs will probably exceed the number of physical CPs by a factor of two to four. And at any point in time, no more units of work than the number of physical CPs in the machine may execute in parallel on all LPARs. The hipervisor, PR/SM, dispatches logical CPs on physical CPs, and the oprtaing system dispatches units of work on the logical CPs. -- Peter Hunkeler
