[Pkg-libvirt-maintainers] Bug#731746: Only half of cpu available using libvirt with AMD Opteron G3 proccessors and wheezy

[LAVOCAT Franck]

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Package: libvirt
Version:  0.9.12-11+deb7u4
Severity: serious

Hello,
We have an improper core usability with our Dell R515/715 Hosts AMD Opteron servers.

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OS : Debian 7.1
Linux vmsrv10 3.2.0-4-amd64 #1 SMP Debian 3.2.46-1 x86_64 GNU/Linux


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System Information
    Manufacturer: Dell Inc.
    Product Name: PowerEdge R715

Processor Information
    Socket Designation: CPU1
    Type: Central Processor
    Family: Opteron 6100
    Manufacturer: AMD
    Signature: Family 16, Model 9, Stepping 1

Processor Information
    Socket Designation: CPU2
    Type: Central Processor
    Family: Opteron 6100
    Manufacturer: AMD
    Signature: Family 16, Model 9, Stepping 1

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While lspcu show :
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                24
On-line CPU(s) list:   0-23
Thread(s) per core:    1
Core(s) per socket:    12
Socket(s):             2
NUMA node(s):          4
Vendor ID:             AuthenticAMD
CPU family:            16
Model:                 9
Stepping:              1
CPU MHz:               2100.360
BogoMIPS:              4200.10
Virtualization:        AMD-V
L1d cache:             64K
L1i cache:             64K
L2 cache:              512K
L3 cache:              5118K
NUMA node0 CPU(s):     0,2,4,6,8,10
NUMA node1 CPU(s):     12,14,16,18,20,22
NUMA node2 CPU(s):     13,15,17,19,21,23
NUMA node3 CPU(s):     1,3,5,7,9,11

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virsh capabilities shows :
  <host>
    <uuid>9522c890-ae6f-514a-c205-96147033a53c</uuid>
    <cpu>
      <arch>x86_64</arch>
      <model>Opteron_G3</model>
      <vendor>AMD</vendor>
      <topology sockets='2' cores='6' threads='1'/>
      <feature name='nodeid_msr'/>
      <feature name='wdt'/>
      <feature name='skinit'/>
      <feature name='ibs'/>
      <feature name='osvw'/>
      <feature name='3dnowprefetch'/>
      <feature name='cr8legacy'/>
      <feature name='extapic'/>
      <feature name='cmp_legacy'/>
      <feature name='3dnow'/>
      <feature name='3dnowext'/>
      <feature name='pdpe1gb'/>
      <feature name='fxsr_opt'/>
      <feature name='mmxext'/>
      <feature name='ht'/>
      <feature name='vme'/>
    </cpu>
    <power_management>
      <suspend_disk/>
    </power_management>
    <migration_features>
      <live/>
      <uri_transports>
        <uri_transport>tcp</uri_transport>
      </uri_transports>
    </migration_features>
    <topology>
      <cells num='4'>
        <cell id='0'>
          <cpus num='6'>
            <cpu id='0'/>
            <cpu id='2'/>
            <cpu id='4'/>
            <cpu id='6'/>
            <cpu id='8'/>
            <cpu id='10'/>
          </cpus>
        </cell>
        <cell id='1'>
          <cpus num='6'>
            <cpu id='12'/>
            <cpu id='14'/>
            <cpu id='16'/>
            <cpu id='18'/>
            <cpu id='20'/>
            <cpu id='22'/>
          </cpus>
        </cell>
        <cell id='2'>
          <cpus num='6'>
            <cpu id='13'/>
            <cpu id='15'/>
            <cpu id='17'/>
            <cpu id='19'/>
            <cpu id='21'/>
            <cpu id='23'/>
          </cpus>
        </cell>
        <cell id='3'>
          <cpus num='6'>
            <cpu id='1'/>
            <cpu id='3'/>
            <cpu id='5'/>
            <cpu id='7'/>
            <cpu id='9'/>
            <cpu id='11'/>
          </cpus>
        </cell>
      </cells>
    </topology>
  </host>

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Trying to affect cpu > 11 lead to error :

virsh vcpupin virtualsrv1 0 12
error: Physical CPU 12 doesn't exist.
error: cpulist: Invalid format.

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By the way we are limited in use to 12 out of our 24 cores for VM possessor affectation.

The problem is fixed since the build version 0.9.3 of libvirt (http://libvirt.org/news.html)
Bug fixes : nodeinfo: Get the correct CPU number on AMD Magny Cours platform (Osier Yang)

Possible correction by upgrading libvirt version to at least v 0.9.3.

Thanks.

--
Bien cordialement,

Franck LAVOCAT
Centre de Ressources Informatiques
T : 01 60 95 74 55
BÂTIMENT Copernic - BUREAU 4B023
franck.lavocat at u-pem.fr
UPEM - Université Paris-Est Marne-la-Vallée
CITÉ DESCARTES - 5 BOULEVARD DESCARTES - CHAMPS-SUR-MARNE
77454 MARNE-LA-VALLÉE CEDEX 2 - www.u-pem.fr