[libvirt-users] Performance issues with KVM

Hello, We are using libvirt over KVM. If we run a single virtual machine on a host then the performance is very good but if more than one vm (with 1:1 provisioning) runs on same host the performance is very poor (specially in case of parallel programming). libvirt version: 0.9.2 qemu-kvm-0.14.1 We are using virtio module also. What could be the possible reasons for this behavior. Please tell me if you need more info. -- Jatin