Re: Packets dropped by virtual NICs

Hi Michal, these are the steps: - start the vm with qemu sudo qemu-system-x86_64-spice -m 2048 -enable-kvm -smp 3 -cdrom /home/machine_A/ubuntu.iso -netdev tap,ifname=tap0,vhost=on,id=n1,vhostforce=on,queues=3,script=/etc/tap0_ifup.sh,downscript=/etc/tap0_ifdown.sh -device virtio-net-pci,netdev=n1,mac=9E:58:00:d2:53:03,mq=on,vectors=8 -netdev tap,ifname=tap1,vhost=on,id=n2,vhostforce=on,queues=3,script=/etc/tap1_ifup.sh,downscript=/etc/tap1_ifdown.sh -device virtio-net-pci,netdev=n2,mac=7A:53:00:d1:59:04,mq=on,vectors=8 -device virtio-net,netdev=network2 -netdev user,id=network2 -hda switch_A.img - attach the tap to the bridges in the host machine (to have the traffic coming from the outsider traffic generator injected in the vm) - in the VM:     - enable ip_forward     - enable promiscuous mode for the interface

    - send the "tc qdisc" command to configure the output NIC with 2 traffic classes (TC) assigned to 2 different queues     - add the iptables mangle rules to the POSTROUTING chain to assign TC1 to the traffic with dport 7777 and TC0 to the traffic with dport 8888 I'm sending 2 UDP flows, I have no loss under 3Mbps each. If I capture traffic with tcpdump on the ingress and on the egress nic (of the VM), I see a difference of 50% of packets When I did a test on the host machine, to check if it has the same problem, I've reached an aggregated traffic of 90Mbps with no loss. That's why I think that there is some misconfiguration on the virtual NIC.