[libvirt] virsh nodeinfo CPU detection questions

Scott Sullivan ssullivan at liquidweb.com
Tue Jan 29 15:52:32 UTC 2013


I have a machine with four AMD Opteron(TM) 6272 processors:

http://www.amd.com/us/products/server/processors/6000-series-platform/6200/Pages/6200-series-processors.aspx#5

I use 'virsh nodeinfo' to determine the amount of physical CPUs, and CPU 
cores. What values should I be looking at in the output of nodeinfo to 
determine this? With 1.X libvirts the output values have changed from 0.9.4:

0.9.4:
[root at host ~]# virsh nodeinfo
CPU model: x86_64
CPU(s): 64
CPU frequency: 2099 MHz
CPU socket(s): 4
Core(s) per socket: 8
Thread(s) per core: 2
NUMA cell(s): 1
Memory size: 24713980 kB
[root at host28 ~]#

1.0.1:
[root at host ~]# virsh nodeinfo
CPU model: x86_64
CPU(s): 64
CPU frequency: 2099 MHz
CPU socket(s): 1
Core(s) per socket: 8
Thread(s) per core: 2
NUMA cell(s): 4
Memory size: 24713980 KiB
[root at host28 ~]#

As you can see, the CPU socket and NUMA cells values have changed in 
these two versions, on the same machine. To get the physical CPU count, 
is it safe to assume this?

Numa cell(s) X CPU Socket(s) == physical CPUs present

However, I am not positive what formula I should use to determine the 
CPU core count. On this processor, it has 16 cores. Would that mean I 
can do this?

Core(s) per socket X Thread(s) per core: == CPU cores

Thanks in advance for clarifying.




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