On Tue, 2011-11-15 at 10:14 +0530, Krishna Kumar2 wrote: > Sasha Levin <levinsasha928@xxxxxxxxx> wrote on 11/14/2011 03:45:40 PM: > > > > Why both the bandwidth and latency performance are dropping so > > > dramatically with multiple VQ? > > > > It looks like theres no hash sync between host and guest, which makes > > the RX VQ change for every packet. This is my guess. > > Yes, I confirmed this happens for macvtap. I am > using ixgbe - it calls skb_record_rx_queue when > a skb is allocated, but sets rxhash when a packet > arrives. Macvtap is relying on record_rx_queue > first ahead of rxhash (as part of my patch making > macvtap multiqueue), hence different skbs result > in macvtap selecting different vq's. I'm seeing this behavior in non-macvtep related setup as well (simple tap <-> virtio-net). -- Sasha. -- 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
