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[Jon Grimm <jgrimm@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

Noticed while testing:  https://blueprints.launchpad.net/nova/+spec
/virt-driver-vcpu-topology


I have a host advertising 16 VCPUs (2 sockets, each 8 cores).   Each core happens to have 8 threads.    (This is on a beefy POWER8 system).    With the above blueprint,  I can now create a 1 socket, 2 core, 8 thread guest.    

All works fine, except that I noticed "Free VCPUS:  0' even though I'm
really only using two cores.    I'd think I would see 14 free VCPUs in
this scenario.

Guest lscpu output: 
[root@bare-precise ~]# lscpu
Architecture:          ppc64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Big Endian
CPU(s):                16
On-line CPU(s) list:   0-15
Thread(s) per core:    8
Core(s) per socket:    2
Socket(s):             1
NUMA node(s):          1
Model:                 IBM pSeries (emulated by qemu)
L1d cache:             64K
L1i cache:             32K
NUMA node0 CPU(s):     0-15

Resulting tracker
2014-08-12 12:17:18.874 96650 AUDIT nova.compute.resource_tracker [-] Free VCPUS: 0

** Affects: nova
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1355921

Title:
  [libvirt] When guest configured for threads, poor VCPU accounting

Status in OpenStack Compute (Nova):
  New

Bug description:
  Noticed while testing:  https://blueprints.launchpad.net/nova/+spec
  /virt-driver-vcpu-topology

  
  I have a host advertising 16 VCPUs (2 sockets, each 8 cores).   Each core happens to have 8 threads.    (This is on a beefy POWER8 system).    With the above blueprint,  I can now create a 1 socket, 2 core, 8 thread guest.    

  All works fine, except that I noticed "Free VCPUS:  0' even though I'm
  really only using two cores.    I'd think I would see 14 free VCPUs in
  this scenario.

  Guest lscpu output: 
  [root@bare-precise ~]# lscpu
  Architecture:          ppc64
  CPU op-mode(s):        32-bit, 64-bit
  Byte Order:            Big Endian
  CPU(s):                16
  On-line CPU(s) list:   0-15
  Thread(s) per core:    8
  Core(s) per socket:    2
  Socket(s):             1
  NUMA node(s):          1
  Model:                 IBM pSeries (emulated by qemu)
  L1d cache:             64K
  L1i cache:             32K
  NUMA node0 CPU(s):     0-15

  Resulting tracker
  2014-08-12 12:17:18.874 96650 AUDIT nova.compute.resource_tracker [-] Free VCPUS: 0

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