If this is for a more-or-less closed system, I wonder why it uses IP, and not an RDMA-type network (Infiniband etc.) which already is kernel-bypass and works ro

If this is for a more-or-less closed system, I wonder why it uses IP, and not an RDMA-type network (Infiniband etc.) which already is kernel-bypass and works routinely at around 100G, 1μs latency. There's nothing special about the Mellanox drivers amongst the Openfabrics ones in having free drivers in Linux, but they generally require blobs or separate firmware.