2 Replies Latest reply: Dec 7, 2010 10:56 AM by 804842 RSS

    Is "Whole-core constraint" meaning 1 or 8 VCPU in Guest Domain in LDom 2.0?

      Hi All,

      I've noticed that LDom version 2.0 (called now Oracle VM Server for SPARC 2.0) has a new feature called "CPU whole core allocation". The documentation says we can create "Whole-Core Constraints" with these commands (notice the "-c" argument in command):
      ldm add-vcpu -c number
      ldm set-vcpu -c number
      ldm remove-vcpu -c number

      We are using here a T5240 server, Solaris 10 on it, currently using LDom 1.1 version, with 3 Guest LDOMs running. This server has T2+ processor, 2 of it. One CPU has 8 cores and one core has 8 threads. So in total 2 CPU x 8 Cores x 8 Threads = 128 threads. That corresponds to 128 VCPU in LDOM point of view.
      If I count the cores, that is 16 cores in total.

      For example, in one of the Guest LDOM, 40 VCPU is allocated:
      -bash-3.00$ psrinfo -pv
      The physical processor has 24 virtual processors (0-23)
      UltraSPARC-T2+ (chipid 0, clock 1165 MHz)
      The physical processor has 16 virtual processors (24-39)
      UltraSPARC-T2+ (chipid 1, clock 1165 MHz)

      When I allocate a complete core to a Guest Domain (using the Whole-core constraint feature), from Guest Domain point of view, it will still appear as 8 VCPU, or it will appear as 1 CPU in the Guest domain? So I wonder whether the whole-core allocation is still splitting the core into threads in the guest domain?

      I read the documentation but this is not very clear to me. I don't have LDom 2.0 installed so cannot test it.

      Thanks a lot in advance