Hi all, I have been deploying two KVMs on my Debian testing box. Two KVMs each use one tap device connecting to the host. When I doing netperf with large package size from KVM2 (tap1) to KVM1 (tap0) using ethX on them, I could verify that TSO did happened by # tcpdump -nt -i tap1 I can see messages like, IP 192.168.101.2.39994 > 192.168.101.1.41316: Flags [P.], seq 7912865:7918657, ack 0, win 92, options [nop,nop,TS val 874151 ecr 874803], length 5792 So, according the 'length', skb didn't get segmented. However, When I (1) setup VLAN using vconfig on KVM2, KVM1, and got two new interface eth1.3003, eth0.3003 on both machines. (2) netperf between two new interface, TSO no longer showed up, # tcpdump -nt -i tap1 I only got, vlan 3003, p 0, IP 10.214.10.2.42324 > 10.214.10.1.56460: Flags [P.], seq 2127976:2129424, ack 1, win 92, options [nop,nop,TS val 926034 ecr 926686], length 1448 So, all the large packages get segmented in virtio (is that right?) My KVM command line options are, kvm -hda $IMG -m 768 -net nic,model=virtio,macaddr=52:54:00:12:34:56 -net tap,ifname=$TAP,script=no My question is whether it is the expected behavior? Can VLAN tagging coexist with TSO in virtio_net driver? If this is not desired result. Any hint for fixing the problem? Thanks -D -- 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
