On Mon, May 18, 2009 at 12:14:34AM +0300, Avi Kivity wrote: > >> No, I am measuring UDP throughput performance. I have now tried using a >> different NIC model, and the e1000 model seems to achieve slightly >> better performance (CPU goes up to 110% only though). I have also been >> running virtio now, and while its performance with 2.6.20 was very poor >> too, when changing the guest kernel to 2.6.30, I get a reasonable >> performance and higher CPU utilization (e.g. it goes up to 180-190%). I >> have to throttle the incoming bandwidth though, because as soon as I go >> over a certain threshold, CPU goes back down to 90% and throughput goes >> down too. > > Yes, there's a known issue with UDP, where we don't report congestion > and the queues start dropping packets. There's a patch for tun queued > for the next merge window; you'll need a 2.6.31 host for that IIRC > (Herbert?) It should be in 2.6.30 in fact. However, this is for outbound traffic only since inbound traffic shouldn't have this problem of the guest sending faster than the wire. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- 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
