I am resending this email as Freddie didn't use 'reply to all' when replying to this message. I am also updating to answer Freddie's questions.. 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? Actually we are having a custom application which just measures ping-pong latency. The results that i get with virtio is around 750 micro seconds. The result i get with emulated e1000 is around 250 micro sec. Also i tried to use vhost but the virtio latency remained the same. Also i tried the tests with guest and host 2.6.26 kernel. I get better results for virtio than e1000. I get 550 for e1000 and 500 for virtio. Actually my application needs as minimum latency as needed. I am ready to trade-off throughput and cpu utilization. I was very excited when i saw the vhost-net module with people claiming low latencies. I am worried that i am missing some performance offered by virtio and vhost. Thanks, Bala -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
