Virtio network performance poorer than emulated e1000

Balachandar
2010-07-22T20:13:30Z

I can see that virtio network performance is poorer than emaulated
e1000 nic. I did some simple ping test and with emulated e1000 the
average rtt is around 600 microsec. With virtio the average rtt is 800
microsec. I am using a tap + bridge configuration. I run kvm as
follows

kvm -m 512 -hda vdisk.img \
-net nic,model=virtio \
-net tap,ifname=tap0,script=qemu-ifup,downscript=no

I am running Debian squeeze distribution with guest and host kernel 2.6.34.

Does anyone else see some results like this or is it only me? Could
changing the distribution help as i am running a testing one?

Thanks,
Bala