[Qemu-devel] how to verify virtio is being used?

[al pat]

I have posted this on kvm alias, but have not heard back. seeing some inputs.

seeking some pointers/guidance as to how to determine virtio is being used...

I configured a VM to use block device with if=virtio (create a 1GB
disk using dd I exported this disk to the VM and am now doing scp from
host to the
 guest after creating partition/mkfs.

I created another 1GB disk and export it as a IDE disk. I use the same
scp command from host to guest after creating partition/mkfs.

I am trying to determine if my block IO is indeed using virtio in the
first case.

Empirically, I observe that with if=virtio, the throughput is about
30% more (in terms of mbps) and time taken is about 40% less than
for the case where I passed the disk as a IDE disk.

My scp happens over virbr0 interface (and currently I am not concerned
if networking is using virtio)

How do I confirm that virtio is being used? Are there any debugs that
I can enable to do that.

I am using ubuntu server (2.6.38-8) as host and ubuntu (2.6.24-29)
client as guest.

Thanks