On Mon, Jul 4, 2016 at 1:34 PM, D3c3 Balus <d3c3ba...@gmail.com> wrote: > Hello, > > I’m using 2 Ubuntu Xenial 16.04 LTS with the following: > - kernel: 4.4.0-28-generic > - OVS version: 2.5.0 (installed from ubuntu packages: openvswitch-common & > openvswitch-switch) > > I’m configuring a GRE tunnel between OVS bridges running on each of the > machines with: > > ovs-vsctl add-port br0 tun0 -- set Interface tun0 type=gre > options:remote_ip=x.x.x.x > > and I achieve connectivity between VMs, as desired, via the GRE tunnel. > > > Problem: iperf test show really low performance (734 bits/sec !!) > considering a baseline that shows almost 1G over the direct link. > > Troubleshooting performed: > 1. increased MTU of the physical link on both sides: `ip link set dev enp0s8 > mtu 2000` => same poor perf > 2. increased MTU of the br0 on both OVS bridges: `ip link set dev br0 mtu > 1700` => same poor perf > > [FYI: I performed the same operations on an older version of Ubuntu = > Trusty 14.04 LTS, kernel 3.13.0-86, and after adjusting the MTU as above, the > GRE performance was satisfactory ~ 414 Mbps !! ]
One data point that would be really useful would be what physical links are you using, specifically what driver and device combination. More often then not these type of issues are due to something like LRO or GRO creating an oversized frame, or the TSO feature advertising support for a tunnel it doesn't actually support. You might go through and verify if any of these features are enabled on the physical link using "ethtool -k" and then go through and disable them until you see the performance improve. Hope that helps. - Alex _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss
