[dpdk-users] ARP reply packet fail to transmit on the wire on 82599ES

[Du, Fan]

hi dpdk and ovs experts

My test bed is pretty simple, setup host1 and host2 with following topology.
I use dpdk-2.0.0 with ovs head commit.

On host1:
kvm guest1 -> dpdkvhostuser -> br-int -> vxlan port -> br-ex -> dpdk port
ifconfig br-ex 192.168.1.2/24

On host2:
kvm guest2 -> dpdkvhostuser -> br-int -> vxlan port -> br-ex -> dpdk port
ifconfig br-ex 192.168.1.4/24

All ovs bridge are on user space, both hosts are connected with DAC 
using 82599ES,
the first packet between guest1 and guest2 triggers arp resolution for 
the vxlan
outer mac address for br-ex ip address.

tcpdump on host1 br-ex with dummy device:
09:32:58.393875 ARP, Request who-has 192.168.1.4 tell 192.168.1.2, length 28

tcpdump on host2 br-ex with dummy device:
21:21:31.766201 ARP, Request who-has 192.168.1.4 tell 192.168.1.2, length 46
21:21:31.766273 ARP, Reply 192.168.1.4 is-at 90:e2:ba:64:f4:05, length 46

It's wired that host1 failed receive ARP Reply packet from host2, so 
guest1 and
guest2 cannot talk to each other. When I replace dpdk port with normal 
net device
ens803f1 using the same NIC physical port, two guests talk to each other 
well.

After some digging, the ARP reply packet did reach on ixgbe tx_pkt_burst 
function,
whether or not RTE_IXGBE_INC_VECTOR is set, ARP reply packet didn't show 
on wire.

This looks like a bug to me, or am I missing something somewhere obviously.
Any suggestions and pointers is appreciated.