I have an host machine with qemu-kvm 2.11.1 (I built it) kernel version 4.6.3-elrepo OS Centos 6
One VM acts as a router and has two bridge connections between the physical interface and the virtual network of the others VMs
I use -netdev and model virtio with vhost=on.
On some cases I see an high cpu load on the host machine of the VM acting as a router, while inside VM 99 cpu is idle.
As I understand, it`s used for emulating network. So question are :
Is there any practical difference beetween model=virtio and vhost=on and virtio-pci-net ?
Is it normal to have the CPU overloaded with just 6 - 7 MBit/s of traffic ( mostly UDP and http requests)
Is there any reason to upgrade kernel
what optimizations are possible?