ceph/src/spdk/dpdk/doc/guides/nics/af_xdp.rst

   1 ..  SPDX-License-Identifier: BSD-3-Clause
   2     Copyright(c) 2019 Intel Corporation.
   3
   4 AF_XDP Poll Mode Driver
   5 ==========================
   6
   7 AF_XDP is an address family that is optimized for high performance
   8 packet processing. AF_XDP sockets enable the possibility for XDP program to
   9 redirect packets to a memory buffer in userspace.
  10
  11 For the full details behind AF_XDP socket, you can refer to
  12 `AF_XDP documentation in the Kernel
  13 <https://www.kernel.org/doc/Documentation/networking/af_xdp.rst>`_.
  14
  15 This Linux-specific PMD driver creates the AF_XDP socket and binds it to a
  16 specific netdev queue, it allows a DPDK application to send and receive raw
  17 packets through the socket which would bypass the kernel network stack.
  18 Current implementation only supports single queue, multi-queues feature will
  19 be added later.
  20
  21 Note that MTU of AF_XDP PMD is limited due to XDP lacks support for
  22 fragmentation.
  23
  24 Options
  25 -------
  26
  27 The following options can be provided to set up an af_xdp port in DPDK.
  28
  29 *   ``iface`` - name of the Kernel interface to attach to (required);
  30 *   ``queue`` - netdev queue id (optional, default 0);
  31
  32 Prerequisites
  33 -------------
  34
  35 This is a Linux-specific PMD, thus the following prerequisites apply:
  36
  37 *  A Linux Kernel (version > v4.18) with XDP sockets configuration enabled;
  38 *  libbpf (within kernel version > v5.1-rc4) with latest af_xdp support installed,
  39    User can install libbpf via `make install_lib` && `make install_headers` in
  40    <kernel src tree>/tools/lib/bpf;
  41 *  A Kernel bound interface to attach to;
  42
  43 Set up an af_xdp interface
  44 -----------------------------
  45
  46 The following example will set up an af_xdp interface in DPDK:
  47
  48 .. code-block:: console
  49
  50     --vdev net_af_xdp,iface=ens786f1,queue=0