From mboxrd@z Thu Jan  1 00:00:00 1970
From: RW <kvm@tauceti.net>
Subject: Re: KVM and cpu limiting
Date: Fri, 02 Jul 2010 10:02:03 +0200
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> Is it possible to limit cpu usage be VM when using qemu+kvm?
>   

First thing you can do is to only provide one or two
virtual CPUs to a VM. This is normally a not to bad
way to limit CPU usage. But maybe cgroups can help
you more:
http://www.mjmwired.net/kernel/Documentation/cgroups.txt

> I need one server to run a lot of VMs (much more than cpu cores I
> have). Each VM must have it's guaranted cpu time or time slice it must
> use.
>
> Is it possible to make such limits? Is it possible to modify
> /proc/cpuinfo of VMs?
>
>   

You can start Qemu/KVM with different "-cpu" parameter:
bern:~ # qemu-kvm -cpu ?
x86           qemu64
x86           phenom
x86         core2duo
x86            kvm64
x86           qemu32
x86          coreduo
x86              486
x86          pentium
x86         pentium2
x86         pentium3
x86           athlon
x86             n270

Or just provied "-cpu host". Then you get the same output
inside the guest as the host.

- Robert