[dpdk-users] Jumbo packets get segmented on RX

[Moessbauer, Felix]

Hi,

I'm trying to send and receive jumbo frame ethernet packets.
While sending works without any issues, I always receive fragmented / segmented packets.

This leads me to the following questions:

  1.  Is it possible to receive a frame without segmentation
  2.  How to properly size the mempool elements. Here, I tried the following (pkt_bytes is the maximum expected frame size):

buf_size = RTE_PKTMBUF_HEADROOM + pkt_bytes;
rte_mempool_create(mempool_name, NB_MBUF, buf_size,
                                             MAX_PKT_BURST, sizeof(struct rte_pktmbuf_pool_private),
                                             rte_pktmbuf_pool_init, NULL,
                                             rte_pktmbuf_init, NULL, rte_socket_id(),
                                             MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET);

Some experiments with various buf_sizes showed, that if I make the buffer large enough (e.g. pkt_bytes * 2) it seems to work at least for some NICs (with IXGBE driver).

DPDK: 20.11-rc1

Best regards,
Felix