Out-of-order DPU packets through BlueField-3 default OVS bridge

Infrastructure & Networking BlueField
1

Hi,

We are starting to use a BlueField-3 DPU for UDP packet reception. In the first stage we plan to use the DPU as standard NIC; later we plan to implement some data processing algorithms. We understand that the default DPU configuration uses Open vSwitch (OVS) with two bridges between the external ports p0/p1 and the host interfaces pf0hpf/pf1hpf, respectively:

ubuntu@localhost:~$ sudo ovs-vsctl show
a62ea93c-1d9e-4ced-95b6-a1af09007491
    Bridge ovsbr1
        Port ovsbr1
            Interface ovsbr1
                type: internal
        Port p0
            Interface p0
        Port pf0hpf
            Interface pf0hpf
        Port en3f0pf0sf0
            Interface en3f0pf0sf0
    Bridge ovsbr2
        Port ovsbr2
            Interface ovsbr2
                type: internal
        Port p1
            Interface p1
        Port pf1hpf
            Interface pf1hpf
        Port en3f1pf1sf0
            Interface en3f1pf1sf0
    ovs_version: "3.2.0044"

Our application uses Jumbo UDP packets, so we configured all the involved ports with mtu 9000. We use two independent 10 GbE links, packets are addressed to dedicated ports on each interface. The first tests only involve a bunch of packets (~128 packets) per interface/port.

However, it seems that we receive the UDP packets out-of-order, something that we never experienced in the past with standard NICs. Do you know what is the origin of this behavior?

Thank you very much in advance for your advice and support.

Kind regards

Alejandro Homs Puron