Re: [dpdk-dev] [PATCH v5] doc: introduce openwrt how-to guide

[Thomas Monjalon <thomas@monjalon.net>]

18/01/2020 06:48, Xiaolong Ye:
> This doc describes how to enable DPDK on Openwrt in both virtual and
> physical x86 environment.
> 
> Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
> ---
> --- /dev/null
> +++ b/doc/guides/howto/openwrt.rst
> +Enable DPDK on openwrt
> +======================
> +
> +This document describes how to enable Data Plane Development Kit (DPDK) on
> +Openwrt in both a virtual and physical x86 environment.

Please take care of the uppercases in OpenWrt.

> +
> +Introduction
> +------------
> +
> +The OpenWrt project is a Linux operating system targeting embedded devices.
> +Instead of trying to create a single, static firmware, OpenWrt provides a fully
> +writable filesystem with package management. This frees the user from the
> +application selection and configuration provided by the vendor and allows users
> +to customize the device through the use of packages to suit any application. For
> +developers OpenWrt is the framework to build an application without having to
> +build a complete firmware around it. For users is offers full customization
> +to use the device in ways never envisioned.

Why doing marketing for OpenWrt in DPDK doc?
It is a copy paste from https://openwrt.org/
I think it is enough to say OpenWrt is a source-based router OS with package management.

> +
> +Pre-requisites
> +~~~~~~~~~~~~~~
> +
> +You need gcc, binutils, bzip2, flex, python3.5+, perl, make, find, grep, diff,
> +unzip, gawk, getopt, subversion, libz-dev and libc headers installed.

These are prerequisites for building, so should be in section below.
Maybe we can just provide a link to the official doc instead.

> +
> +Build OpenWrt
> +-------------
> +
> +You can obtain OpenWrt image through https://downloads.openwrt.org/releases. To

Please take the habit of splitting lines after a punctuation.

> +fully customize your own OpenWrt, it is highly recommended to build it from
> +the source code. You can clone the OpenWrt source code as follows:
> +
> +.. code-block:: console
> +
> +    git clone https://git.openwrt.org/openwrt/openwrt.git
> +
> +OpenWrt configuration
> +~~~~~~~~~~~~~~~~~~~~~
> +
> +* Select ``x86`` in ``Target System``
> +* Select ``x86_64`` in ``Subtarget``
> +* Select ``Build the OpenWrt SDK`` for cross-compilation environment
> +* Select ``Use glibc`` in ``Advanced configuration options (for developers)``
> +  then ``ToolChain Options`` and ``C Library implementation``
> +
> +Kernel configuration
> +~~~~~~~~~~~~~~~~~~~~
> +
> +The following configurations should be enabled:
> +
> +* ``CONFIG_UIO=y``

No, UIO is not recommended anymore.

> +* ``CONFIG_HUGETLBFS=y``
> +* ``CONFIG_HUGETLB_PAGE=y``
> +* ``CONFIG_PAGE_MONITOR=y``

Why PAGE_MONITOR?

> +
> +Build steps
> +~~~~~~~~~~~
> +
> +For detailed OpenWrt build steps, please refer to the
> +`OpenWrt build guide
> +<https://openwrt.org/docs/guide-developer/build-system/use-buildsystem>`_.
> +
> +After the build is completed, you can find the images and sdk in
> +``<OpenWrt Root>/bin/targets/x86/64-glibc/``.

s/sdk/SDK/

[...]
> +    [binaries]
> +    c = 'x86_64-openwrt-linux-gcc'
> +    cpp = 'x86_64-openwrt-linux-cpp'
> +    ar = 'x86_64-openwrt-linux-ar'
> +    strip = 'x86_64-openwrt-linux-strip'
> +
> +    meson builddir --cross-file openwrt-cross

This is really a good example why meson should allow to override the toolchain prefix.
Please work with meson on this topic.

[...]
> +To cross compile with make:
> +
> +.. code-block:: console
> +
> +    export STAGING_DIR=<OpenWrt sdk>/glibc/openwrt-sdk-x86-64_gcc-8.3.0_glibc.Linux-x86_64/staging_dir
> +    export RTE_SDK=`pwd`
> +    export RTE_KERNELDIR=<OpenWrt Root>/build_dir/target-x86_64_glibc/linux-x86_64/linux-4.19.81/
> +    make config T=x86_64-native-linuxapp-gcc
> +    make -j 100 CROSS=x86_64-openwrt-linux-gnu-

The make build system should not be documented as it is going to be deprecated.

> +
> +Running DPDK application on OpenWrt
> +-----------------------------------
> +
> +Virtual machine
> +~~~~~~~~~~~~~~~
> +
> +* Extract the boot image
> +
> +.. code-block:: console
> +
> +    gzip -d openwrt-x86-64-combined-ext4.img.gz
> +
> +* Launch Qemu
> +
> +.. code-block:: console
> +
> +    qemu-system-x86_64 \
> +            -cpu host \
> +            -smp 8 \
> +            -enable-kvm \
> +            -M q35 \
> +            -m 2048M \
> +            -object memory-backend-file,id=mem,size=2048M,mem-path=/tmp/hugepages,share=on \
> +            -drive file=<Your OpenWrt images folder>/openwrt-x86-64-combined-ext4.img,id=d0,if=none,bus=0,unit=0 \
> +            -device ide-hd,drive=d0,bus=ide.0 \
> +            -net nic,vlan=0 \
> +            -net nic,vlan=1 \
> +            -net user,vlan=1 \
> +            -display none \
> +
> +
> +Physical machine
> +~~~~~~~~~~~~~~~~
> +
> +If you are using a Windows PC, you can use an image writer application such as
> +``Win32 Disk Imager`` and ``Etcher`` to write the OpenWrt image
> +(openwrt-x86-64-combined-ext4.img) to a USB flash driver or SDcard.

If you just built a DPDK for Linux, you are not running Windows,
except if you are using a Linux server for compilation.
Anyway, we should not try to document such procedure in my opinion.
I'm sure you can refer to the OpenWrt documentation for flashing the image.

> +
> +If you are using Linux, you can use the ``dd`` tool to write the OpenWrt image
> +to the drive you want to write the image on.
> +
> +.. code-block:: console
> +
> +    dd if=openwrt-18.06.1-x86-64-combined-squashfs.img of=/dev/sdX
> +
> +Where sdX is name of the drive. (You can find it though ``fdisk -l``)
> +
> +Running DPDK
> +~~~~~~~~~~~~
> +
> +More detailed info about how to run a DPDK application please refer to
> +``Running DPDK Applications`` section of :ref:`the DPDK documentation <linux_gsg>`.
> +
> +.. note::
> +
> +    You need to install pre-built numa libraries (including soft link)

s/numa/NUMA/

> +    to /usr/lib64 in OpenWrt.

libnuma is not packaged in OpenWrt?


> --- a/doc/guides/rel_notes/release_20_02.rst
> +++ b/doc/guides/rel_notes/release_20_02.rst
> @@ -116,6 +116,10 @@ New Features
>  
>    Added support for ESP rte_flow patterns to the testpmd application.
>  
> +* **Added OpenWrt howto guide.**
> +
> +  Added document describes how to enable DPDK on OpenWrt in both virtual and
> +  physical machine.
>  
>  Removed Items
>  -------------

You miss a doubled blank line before this title.