d3e94faf91
queue= parameter does not exist.
It might have been the previous name of the queue_count parameter, but
anyway, the default value 1 for the number of queues works fine.
Fixes: f1debd77ef ("net/af_xdp: introduce AF_XDP PMD")
Cc: stable@dpdk.org
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Xiaolong Ye <xiaolong.ye@intel.com>
60 lines
2.2 KiB
ReStructuredText
60 lines
2.2 KiB
ReStructuredText
.. SPDX-License-Identifier: BSD-3-Clause
|
|
Copyright(c) 2019 Intel Corporation.
|
|
|
|
AF_XDP Poll Mode Driver
|
|
==========================
|
|
|
|
AF_XDP is an address family that is optimized for high performance
|
|
packet processing. AF_XDP sockets enable the possibility for XDP program to
|
|
redirect packets to a memory buffer in userspace.
|
|
|
|
For the full details behind AF_XDP socket, you can refer to
|
|
`AF_XDP documentation in the Kernel
|
|
<https://www.kernel.org/doc/Documentation/networking/af_xdp.rst>`_.
|
|
|
|
This Linux-specific PMD driver creates the AF_XDP socket and binds it to a
|
|
specific netdev queue, it allows a DPDK application to send and receive raw
|
|
packets through the socket which would bypass the kernel network stack.
|
|
Current implementation only supports single queue, multi-queues feature will
|
|
be added later.
|
|
|
|
Note that MTU of AF_XDP PMD is limited due to XDP lacks support for
|
|
fragmentation.
|
|
|
|
AF_XDP PMD enables need_wakeup flag by default if it is supported. This
|
|
need_wakeup feature is used to support executing application and driver on the
|
|
same core efficiently. This feature not only has a large positive performance
|
|
impact for the one core case, but also does not degrade 2 core performance and
|
|
actually improves it for Tx heavy workloads.
|
|
|
|
Options
|
|
-------
|
|
|
|
The following options can be provided to set up an af_xdp port in DPDK.
|
|
|
|
* ``iface`` - name of the Kernel interface to attach to (required);
|
|
* ``start_queue`` - starting netdev queue id (optional, default 0);
|
|
* ``queue_count`` - total netdev queue number (optional, default 1);
|
|
* ``pmd_zero_copy`` - enable zero copy or not (optional, default 0);
|
|
|
|
Prerequisites
|
|
-------------
|
|
|
|
This is a Linux-specific PMD, thus the following prerequisites apply:
|
|
|
|
* A Linux Kernel (version > v4.18) with XDP sockets configuration enabled;
|
|
* libbpf (within kernel version > v5.1-rc4) with latest af_xdp support installed,
|
|
User can install libbpf via `make install_lib` && `make install_headers` in
|
|
<kernel src tree>/tools/lib/bpf;
|
|
* A Kernel bound interface to attach to;
|
|
* For need_wakeup feature, it requires kernel version later than v5.3-rc1;
|
|
|
|
Set up an af_xdp interface
|
|
-----------------------------
|
|
|
|
The following example will set up an af_xdp interface in DPDK:
|
|
|
|
.. code-block:: console
|
|
|
|
--vdev net_af_xdp,iface=ens786f1
|