[Xen-users] Looking for clarity about physical cores/cpus and VCPUs

[Kayvan Sylvan <kayvan@xxxxxxxxx>]

Hi everyone,

 

I’m looking for a clear explanation of how the CPU scheduling works and the correspondence between physical CPUs and VCPUS.

 

The Xen manuals state that there is “up to 32 virtual CPUs per guest virtual machine”.

 

So, If I have a server with 64 physical CPUs, and I boot into Xen, with dom0_max_vcpu set to 1, and I have 2 guest domains, like this:

 

Dom0 (1 vcpu)

Guest1 (15 vcpu)

Guest2 (16 vcpu)

 

What is the actual correspondence between the virtual CPUs and physical CPUs?

 

If there is up to 32 vcpus per guest, can I exceed the number of physical CPUs? For example:

 

Dom0 (4 vcpu)

Guest1 (32 vcpu)

Guest2 (32 vcpu)

Guest3 (32 vcpu)

 

 If I do that, how does Xen operate?

 

Thank you very much for your answers.

 

---Kayvan

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users