[CentOS] How to list virt machine size with virsh?

[Dennis Jacobfeuerborn]

On 12/09/2011 01:18 PM, James Hogarth wrote:
>> What I miss in that overview is the memory size of clients. I found
>> "virsh dominfo<client>" but that is for just that one client (and I
>> have several running).
>> The same question for "xm top". I found that there seems to exist
>> virt-top, but I could not find this in a repository for Centos5.
>>
>
> For the memory thing off the top of my head I can't think of anything
> in a single command... but a quick virsh list | awk '$2 ~ /running/
> {print $1}' | while read guest; do virsh dominfo $guest | grep
> memorything .... adapted slightly since that's untested and just
> quickly knocked out from rough memory shoudl help...
>
> With regards to virt-top that's on CentOS 6 .... for the underlying
> hosts you really want to be on C6 rather than C5 at this point due to
> much improved libvirt/kvm features - things like ksm and transparent
> huge pages are new and help... and then things like the newer
> scheduler and kernel is a bonus...

Are there any real-world numbers of ksm in action out there? Just like with 
disk de-duplication I'm really wondering how much this actually buys you.

Regards,
   Dennis