[Qemu-devel] [Bug 1090726] [NEW] qemu does not generate guest cpu topology properly

[Ivelin Slavov]

Public bug reported:

Adding the option

-smp 12,sockets=2,cores=6,threads=1

exposes


Machine (12GB)
  Socket #0
        L2 L#0 (512KB) + L1 L#0 (64KB) + Core L#0 + PU L#0 (P#0)
        L2 L#1 (512KB) + L1 L#1 (64KB) + Core L#1 + PU L#1 (P#1)
        L2 L#2 (512KB) + L1 L#2 (64KB) + Core L#2 + PU L#2 (P#2)
        L2 L#3 (512KB) + L1 L#3 (64KB) + Core L#3 + PU L#3 (P#3)
        L2 L#4 (512KB) + L1 L#4 (64KB) + Core L#4 + PU L#4 (P#4)
        L2 L#5 (512KB) + L1 L#5 (64KB) + Core L#5 + PU L#5 (P#5)
        L2 L#6 (512KB) + L1 L#6 (64KB) + Core L#6 + PU L#6 (P#6)
        L2 L#7 (512KB) + L1 L#7 (64KB) + Core L#7 + PU L#7 (P#7)
  Socket #1
      L2 L#8 (512KB) + L1 L#8 (64KB) + Core L#8 + PU L#8 (P#8)
      L2 L#9 (512KB) + L1 L#9 (64KB) + Core L#9 + PU L#9 (P#9)
      L2 L#10 (512KB) + L1 L#10 (64KB) + Core L#10 + PU L#10 (P#10)
      L2 L#11 (512KB) + L1 L#11 (64KB) + Core L#11 + PU L#11 (P#11)


Rather than:

Machine (12GB)
  Socket #0
        L2 L#0 (512KB) + L1 L#0 (64KB) + Core L#0 + PU L#0 (P#0)
        L2 L#1 (512KB) + L1 L#1 (64KB) + Core L#1 + PU L#1 (P#1)
        L2 L#2 (512KB) + L1 L#2 (64KB) + Core L#2 + PU L#2 (P#2)
        L2 L#3 (512KB) + L1 L#3 (64KB) + Core L#3 + PU L#3 (P#3)
        L2 L#4 (512KB) + L1 L#4 (64KB) + Core L#4 + PU L#4 (P#4)
        L2 L#5 (512KB) + L1 L#5 (64KB) + Core L#5 + PU L#5 (P#5)
  Socket #1
        L2 L#6 (512KB) + L1 L#6 (64KB) + Core L#6 + PU L#6 (P#6)
        L2 L#7 (512KB) + L1 L#7 (64KB) + Core L#7 + PU L#7 (P#7)
        L2 L#8 (512KB) + L1 L#8 (64KB) + Core L#8 + PU L#8 (P#8)
        L2 L#9 (512KB) + L1 L#9 (64KB) + Core L#9 + PU L#9 (P#9)
        L2 L#10 (512KB) + L1 L#10 (64KB) + Core L#10 + PU L#10 (P#10)
        L2 L#11 (512KB) + L1 L#11 (64KB) + Core L#11 + PU L#11 (P#11)


Here is a cpuid dump from inside the guest and dump from more recent version of 
cpuid, in which you can see a bit more detail. The later contains data for a 
single CPU, because the others are the same.

Reproducible on qemu 1.0 and 1.2. with guest os Fedora 17, Debian 6,
Debian Squeeze and Windows 2008 R2.

** Affects: qemu
     Importance: Undecided
         Status: New


** Tags: cpu topology

** Attachment added: "cpuid"
   https://bugs.launchpad.net/bugs/1090726/+attachment/3460611/+files/cpuid

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https://bugs.launchpad.net/bugs/1090726

Title:
  qemu does not generate guest cpu topology properly

Status in QEMU:
  New

Bug description:
  Adding the option

  -smp 12,sockets=2,cores=6,threads=1

  exposes

  
  Machine (12GB)
    Socket #0
          L2 L#0 (512KB) + L1 L#0 (64KB) + Core L#0 + PU L#0 (P#0)
          L2 L#1 (512KB) + L1 L#1 (64KB) + Core L#1 + PU L#1 (P#1)
          L2 L#2 (512KB) + L1 L#2 (64KB) + Core L#2 + PU L#2 (P#2)
          L2 L#3 (512KB) + L1 L#3 (64KB) + Core L#3 + PU L#3 (P#3)
          L2 L#4 (512KB) + L1 L#4 (64KB) + Core L#4 + PU L#4 (P#4)
          L2 L#5 (512KB) + L1 L#5 (64KB) + Core L#5 + PU L#5 (P#5)
          L2 L#6 (512KB) + L1 L#6 (64KB) + Core L#6 + PU L#6 (P#6)
          L2 L#7 (512KB) + L1 L#7 (64KB) + Core L#7 + PU L#7 (P#7)
    Socket #1
        L2 L#8 (512KB) + L1 L#8 (64KB) + Core L#8 + PU L#8 (P#8)
        L2 L#9 (512KB) + L1 L#9 (64KB) + Core L#9 + PU L#9 (P#9)
        L2 L#10 (512KB) + L1 L#10 (64KB) + Core L#10 + PU L#10 (P#10)
        L2 L#11 (512KB) + L1 L#11 (64KB) + Core L#11 + PU L#11 (P#11)

  
  Rather than:

  Machine (12GB)
    Socket #0
          L2 L#0 (512KB) + L1 L#0 (64KB) + Core L#0 + PU L#0 (P#0)
          L2 L#1 (512KB) + L1 L#1 (64KB) + Core L#1 + PU L#1 (P#1)
          L2 L#2 (512KB) + L1 L#2 (64KB) + Core L#2 + PU L#2 (P#2)
          L2 L#3 (512KB) + L1 L#3 (64KB) + Core L#3 + PU L#3 (P#3)
          L2 L#4 (512KB) + L1 L#4 (64KB) + Core L#4 + PU L#4 (P#4)
          L2 L#5 (512KB) + L1 L#5 (64KB) + Core L#5 + PU L#5 (P#5)
    Socket #1
          L2 L#6 (512KB) + L1 L#6 (64KB) + Core L#6 + PU L#6 (P#6)
          L2 L#7 (512KB) + L1 L#7 (64KB) + Core L#7 + PU L#7 (P#7)
          L2 L#8 (512KB) + L1 L#8 (64KB) + Core L#8 + PU L#8 (P#8)
          L2 L#9 (512KB) + L1 L#9 (64KB) + Core L#9 + PU L#9 (P#9)
          L2 L#10 (512KB) + L1 L#10 (64KB) + Core L#10 + PU L#10 (P#10)
          L2 L#11 (512KB) + L1 L#11 (64KB) + Core L#11 + PU L#11 (P#11)

  
  Here is a cpuid dump from inside the guest and dump from more recent version 
of cpuid, in which you can see a bit more detail. The later contains data for a 
single CPU, because the others are the same.

  Reproducible on qemu 1.0 and 1.2. with guest os Fedora 17, Debian 6,
  Debian Squeeze and Windows 2008 R2.

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