How much VCPUs should be assigned to my VMs

[Christian Reiter]

Hello!

I am quite unsure about how much VCPUs should be asssigned to my domU-VMs.
I have here an 4-way SMP Box running 3 to 4 Guests.

Mit freundlichen Grüßen,  ///  Kind Regards,
                                                 Christian Reiter

[Rik van Riel]

Christian Reiter wrote:
> I am quite unsure about how much VCPUs should be asssigned to my domU-VMs.
> I have here an 4-way SMP Box running 3 to 4 Guests.

How much CPU time does each guest use?

A guest that occasionally needs all 4 CPUs might benefit
from having 4 VCPUs, but a guest that uses very little
CPU might hurt from doing cross-cpu synchronization
internally.

[Christian Reiter]

Hello Rik!

Rik van Riel schrieb:
> How much CPU time does each guest use?

I am not abolutely sure at this time....
> A guest that occasionally needs all 4 CPUs might benefit
> from having 4 VCPUs, but a guest that uses very little
> CPU might hurt from doing cross-cpu synchronization
> internally.

So i assume assigning VCPUs to a guest is just the same as
configuring a real SMP system?

Mit freundlichen Grüßen,  ///  Kind Regards,
                                                  Christian Reiter