Low Speed on VxLAN Tunnel using OVS

Hi,I have two hosts and I install OVS on both of them.Now I want to run Vxlan between this two switches.

The commands I use for Vxlan tunnel on first switch:

ovs-vsctl add-br br0
ovs-vsctl add-port br0 vxlan0 -- set Interface vxlan0 type=vxlan \ options:remote_ip=172.30.0.103
ovs-vsctl add-port br0 vi0 -- set Interface vi0 type=internal
ip link set dev vi0 up
ip a add 10.11.12.13/24 dev vi0

and similarly for other switch:
ovs-vsctl add-br br0
ovs-vsctl add-port br0 vxlan0 -- set Interface vxlan0 type=vxlan\ options:remote_ip=172.30.201.61
ovs-vsctl add-port br0 vi0 -- set Interface vi0 type=internal
ip link set dev vi0 up
ip a add 10.11.12.14/24 dev vi0

And now i can ping 10.11.12.14 from the other side of the tunnel (with lower than 1ms latency) and everything works just fine.

​

The problem is low bandwidth on tunnel interface.

when on host1 (with ip 172.30.201.61) I iperf to hosts2(172.30.0.103), The output shows near 1Gbps. but when i use tunnel interfaces for iperf, The output shows near 100Kbps.

I have Googled around but had no luck finding any useful document. Does anyone have an idea why the bandwidth is too low?

BTW: I try this type of configuration too and get same results.
ovs-vsctl add-port br0 vxlan1 -- set interface vxlan1 type=vxlan options:remote_ip=172.30.201.61 options:key=43

Thanks!