Re: [Xen-ia64-devel] problems with smp

[Alex Williamson <alex.williamson@xxxxxx>]

On Thu, 2007-02-08 at 09:10 -0800, David Brown wrote:

> Okay thanks, so this may seem like a dumb question but, if I have 8
> other domUs running all with one vcpu is the xen kernel still going to
> use the other cpus? and does `xm top` show the current cpu usage for
> the system then (all xen cpus) regardless of how many cpus are on
> dom0?

   All of the CPUs exposed to dom0 and domUs are virtual CPUs.  Xen
schedules virtual CPUs across the physical CPUs just like a bare metal
OS schedules processes across physical CPUs.  The xm top output shows
vCPU processor usage across all the vCPUs in a domain.  The CPU% shown
is the percentage of physical CPU time taken.  So 100% means the domain
is consuming all the time of one physical CPU.  A 4-way domain might
consume up to 400%.  One vCPU cannot consume more than one physical CPU,
so if you have less vCPUs (across all domains) than you do pCPUs, then
you won't be able to fully utilize the extra pCPUs.  Does that help?
Thanks,

        Alex 

-- 
Alex Williamson                             HP Open Source & Linux Org.


_______________________________________________
Xen-ia64-devel mailing list
Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ia64-devel