On Tue, Oct 29, 2013 at 06:18:05PM +0100, folkert wrote: > > > > 2. Get the system into the bad state and then do some deeper. Start > > > > with outgoing ping, instrument guest driver and host vhost_net > > > > functions to see what the drivers are doing, inspect the transmit > > > > vring, etc. > > Update: have not gotten around to reboot the server for the new kernel > with those probes, but: it is definately very much worse on tuesday(!) > and when I use mosh to remotely login. If you're hitting the oversized GSO packet issue that Christian Theune also seems to be hitting, then further debugging isn't necessary on your part. When guest network tx is stalled, please check the following on the host: (host)# ifconfig vnet0 vnet0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 inet 192.168.122.123 netmask 255.255.255.0 broadcast 192.168.122.255 ether 52:54:00:bb:01:ac txqueuelen 0 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 1 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 If you see "RX dropped" greater than zero then it's probably the same issue. Stefan -- 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