Re: [dpdk-dev] [PATCH v2 1/6] net/af_xdp: introduce AF XDP PMD driver

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, Mar 19, 2019 at 09:16:27AM -0700, Stephen Hemminger wrote:
> On Tue, 19 Mar 2019 15:12:51 +0800
> Xiaolong Ye <xiaolong.ye@intel.com> wrote:
> 
> > Add a new PMD driver for AF_XDP which is a proposed faster version of
> > AF_PACKET interface in Linux. More info about AF_XDP, please refer to [1]
> > [2].
> > 
> > This is the vanilla version PMD which just uses a raw buffer registered as
> > the umem.
> > 
> > [1] https://fosdem.org/2018/schedule/event/af_xdp/
> > [2] https://lwn.net/Articles/745934/
> > 
> > Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
> > ---
> >  MAINTAINERS                                   |   6 +
> >  config/common_base                            |   5 +
> >  config/common_linux                           |   1 +
> >  doc/guides/nics/af_xdp.rst                    |  45 +
> >  doc/guides/nics/features/af_xdp.ini           |  11 +
> >  doc/guides/nics/index.rst                     |   1 +
> >  doc/guides/rel_notes/release_19_05.rst        |   7 +
> >  drivers/net/Makefile                          |   1 +
> >  drivers/net/af_xdp/Makefile                   |  33 +
> >  drivers/net/af_xdp/meson.build                |  21 +
> >  drivers/net/af_xdp/rte_eth_af_xdp.c           | 930 ++++++++++++++++++
> >  drivers/net/af_xdp/rte_pmd_af_xdp_version.map |   3 +
> >  drivers/net/meson.build                       |   1 +
> >  mk/rte.app.mk                                 |   1 +
> >  14 files changed, 1066 insertions(+)
> >  create mode 100644 doc/guides/nics/af_xdp.rst
> >  create mode 100644 doc/guides/nics/features/af_xdp.ini
> >  create mode 100644 drivers/net/af_xdp/Makefile
> >  create mode 100644 drivers/net/af_xdp/meson.build
> >  create mode 100644 drivers/net/af_xdp/rte_eth_af_xdp.c
> >  create mode 100644 drivers/net/af_xdp/rte_pmd_af_xdp_version.map
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 452b8eb82..1cc54b439 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -468,6 +468,12 @@ M: John W. Linville <linville@tuxdriver.com>
> >  F: drivers/net/af_packet/
> >  F: doc/guides/nics/features/afpacket.ini
> >  
> > +Linux AF_XDP
> > +M: Xiaolong Ye <xiaolong.ye@intel.com>
> > +M: Qi Zhang <qi.z.zhang@intel.com>
> > +F: drivers/net/af_xdp/
> > +F: doc/guides/nics/features/af_xdp.rst
> > +
> >  Amazon ENA
> >  M: Marcin Wojtas <mw@semihalf.com>
> >  M: Michal Krawczyk <mk@semihalf.com>
> > diff --git a/config/common_base b/config/common_base
> > index 0b09a9348..4044de205 100644
> > --- a/config/common_base
> > +++ b/config/common_base
> > @@ -416,6 +416,11 @@ CONFIG_RTE_LIBRTE_VMXNET3_DEBUG_TX_FREE=n
> >  #
> >  CONFIG_RTE_LIBRTE_PMD_AF_PACKET=n
> >  
> > +#
> > +# Compile software PMD backed by AF_XDP sockets (Linux only)
> > +#
> > +CONFIG_RTE_LIBRTE_PMD_AF_XDP=n
> > +
> >  #
> >  # Compile link bonding PMD library
> >  #
> > diff --git a/config/common_linux b/config/common_linux
> > index 75334273d..0b1249da0 100644
> > --- a/config/common_linux
> > +++ b/config/common_linux
> > @@ -19,6 +19,7 @@ CONFIG_RTE_LIBRTE_VHOST_POSTCOPY=n
> >  CONFIG_RTE_LIBRTE_PMD_VHOST=y
> >  CONFIG_RTE_LIBRTE_IFC_PMD=y
> >  CONFIG_RTE_LIBRTE_PMD_AF_PACKET=y
> > +CONFIG_RTE_LIBRTE_PMD_AF_XDP=y
> >  CONFIG_RTE_LIBRTE_PMD_SOFTNIC=y
> >  CONFIG_RTE_LIBRTE_PMD_TAP=y
> >  CONFIG_RTE_LIBRTE_AVP_PMD=y
> > diff --git a/doc/guides/nics/af_xdp.rst b/doc/guides/nics/af_xdp.rst
> > new file mode 100644
> > index 000000000..dd5654dd1
> > --- /dev/null
> > +++ b/doc/guides/nics/af_xdp.rst
> > @@ -0,0 +1,45 @@
> > +..  SPDX-License-Identifier: BSD-3-Clause
> > +    Copyright(c) 2018 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.
> > +
> > +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);
> > +*   ``queue`` - netdev queue id (optional, default 0);
> > +
> > +Prerequisites
> > +-------------
> > +
> > +This is a Linux-specific PMD, thus the following prerequisites apply:
> > +
> > +*  A Linux Kernel (version > 4.18) with XDP sockets configuration enabled;
> > +*  libbpf (within kernel version > 5.1) with latest af_xdp support installed
> > +*  A Kernel bound interface to attach to.
> > +
> > +Set up an af_xdp interface
> > +-----------------------------
> > +
> > +The following example will set up an af_xdp interface in DPDK:
> > +
> > +.. code-block:: console
> > +
> > +    --vdev eth_af_xdp,iface=ens786f1,queue=0
> > diff --git a/doc/guides/nics/features/af_xdp.ini b/doc/guides/nics/features/af_xdp.ini
> > new file mode 100644
> > index 000000000..7b8fcce00
> > --- /dev/null
> > +++ b/doc/guides/nics/features/af_xdp.ini
> > @@ -0,0 +1,11 @@
> > +;
> > +; Supported features of the 'af_xdp' network poll mode driver.
> > +;
> > +; Refer to default.ini for the full list of available PMD features.
> > +;
> > +[Features]
> > +Link status          = Y
> > +MTU update           = Y
> > +Promiscuous mode     = Y
> > +Stats per queue      = Y
> > +x86-64               = Y
> > \ No newline at end of file
> 
> 
> This is bad. Configure your editor to always put newline at end of file.
> In .emacs
> 
>    (setq require-final-newline t)
> 
Or use Vim which needs no extra configuration to do this. :-)