[virt-tools-list] Question about CPU % virt-top
Richard W.M. Jones
rjones at redhat.com
Thu Nov 4 17:59:36 UTC 2010
On Thu, Nov 04, 2010 at 01:51:25PM -0400, Hui Kang wrote:
> Hi, Richard
> I have a question about using virt-top to show the physical CPU %. My
> physical machine has 2 physical CPUs.
> I am running 2 VM and both run CPU-bomb programs.
> When I enter the physical cpu mode (virt-top -1), I found that the CPU usage
> shown on the top of the screen is no more than 100%. However, inside both
> VM, I observer a 100% CPU usage by vmstat.
> Since my machine has 2 CPUs, should the number shown in virt-top be 200% (or
> > 100%)? Thanks.
No because it is scaled to 100% being the total capacity of your host.
This explains how %CPU is calculated:
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-top is 'top' for virtual machines. Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
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