..  SPDX-License-Identifier: BSD-3-Clause
    Copyright(c) 2010-2014 Intel Corporation.

System Requirements
===================

This chapter describes the packages required to compile the DPDK.

.. note::

    If the DPDK is being used on an Intel® Communications Chipset 89xx Series platform,
    please consult the *Intel® Communications Chipset 89xx Series Software for Linux Getting Started Guide*.

BIOS Setting Prerequisite on x86
--------------------------------

For the majority of platforms, no special BIOS settings are needed to use basic DPDK functionality.
However, for additional HPET timer and power management functionality,
and high performance of small packets, BIOS setting changes may be needed.
Consult the section on :ref:`Enabling Additional Functionality <Enabling_Additional_Functionality>`
for more information on the required changes.

.. note::

   If UEFI secure boot is enabled, the Linux kernel may disallow the use of
   UIO on the system. Therefore, devices for use by DPDK should be bound to the
   ``vfio-pci`` kernel module rather than ``igb_uio`` or ``uio_pci_generic``.
   For more details see :ref:`linux_gsg_binding_kernel`.

Compilation of the DPDK
-----------------------

**Required Tools and Libraries:**

.. note::

    The setup commands and installed packages needed on various systems may be different.
    For details on Linux distributions and the versions tested, please consult the DPDK Release Notes.

*   General development tools including ``make``, and a supported C compiler such as ``gcc`` (version 4.9+) or ``clang`` (version 3.4+).

    * For RHEL/Fedora systems these can be installed using ``dnf groupinstall "Development Tools"``

    * For Ubuntu/Debian systems these can be installed using ``apt install build-essential``

*   Python, recommended version 3.5+.

    * Python v3.5+ is needed to build DPDK using meson and ninja

    * Python 2.7+ or 3.2+, to use various helper scripts included in the DPDK package.

*   Meson (version 0.47.1+) and ninja

    * ``meson`` & ``ninja-build`` packages in most Linux distributions

    * If the packaged version is below the minimum version, the latest versions
      can be installed from Python's "pip" repository: ``pip3 install meson ninja``

*   Library for handling NUMA (Non Uniform Memory Access).

    * ``numactl-devel`` in RHEL/Fedora;

    * ``libnuma-dev`` in Debian/Ubuntu;

*   Linux kernel headers or sources required to build kernel modules.

.. note::

   Please ensure that the latest patches are applied to third party libraries
   and software to avoid any known vulnerabilities.


**Optional Tools:**

*   Intel® C++ Compiler (icc). For installation, additional libraries may be required.
    See the icc Installation Guide found in the Documentation directory under the compiler installation.

*   IBM® Advance ToolChain for Powerlinux. This is a set of open source development tools and runtime libraries
    which allows users to take leading edge advantage of IBM's latest POWER hardware features on Linux. To install
    it, see the IBM official installation document.

**Additional Libraries**

A number of DPDK components, such as libraries and poll-mode drivers (PMDs) have additional dependencies.
For DPDK builds using meson, the presence or absence of these dependencies will be
automatically detected enabling or disabling the relevant components appropriately.

For builds using make, these components are disabled in the default configuration and
need to be enabled manually by changing the relevant setting to "y" in the build configuration file
i.e. the ``.config`` file in the build folder.

In each case, the relevant library development package (``-devel`` or ``-dev``) is needed to build the DPDK components.

For libraries the additional dependencies include:

*   libarchive: for some unit tests using tar to get their resources.

*   jansson: to compile and use the telemetry library.

*   libelf: to compile and use the bpf library.

For poll-mode drivers, the additional dependencies for each driver can be
found in that driver's documentation in the relevant DPDK guide document,
e.g. :doc:`../nics/index`


Running DPDK Applications
-------------------------

To run an DPDK application, some customization may be required on the target machine.

System Software
~~~~~~~~~~~~~~~

**Required:**

*   Kernel version >= 3.16

    The kernel version required is based on the oldest long term stable kernel available
    at kernel.org when the DPDK version is in development.
    Compatibility for recent distribution kernels will be kept, notably RHEL/CentOS 7.

    The kernel version in use can be checked using the command::

        uname -r

*   glibc >= 2.7 (for features related to cpuset)

    The version can be checked using the ``ldd --version`` command.

*   Kernel configuration

    In the Fedora OS and other common distributions, such as Ubuntu, or Red Hat Enterprise Linux,
    the vendor supplied kernel configurations can be used to run most DPDK applications.

    For other kernel builds, options which should be enabled for DPDK include:

    *   HUGETLBFS

    *   PROC_PAGE_MONITOR  support

    *   HPET and HPET_MMAP configuration options should also be enabled if HPET  support is required.
        See the section on :ref:`High Precision Event Timer (HPET) Functionality <High_Precision_Event_Timer>` for more details.

.. _linux_gsg_hugepages:

Use of Hugepages in the Linux Environment
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Hugepage support is required for the large memory pool allocation used for packet buffers
(the HUGETLBFS option must be enabled in the running kernel as indicated the previous section).
By using hugepage allocations, performance is increased since fewer pages are needed,
and therefore less Translation Lookaside Buffers (TLBs, high speed translation caches),
which reduce the time it takes to translate a virtual page address to a physical page address.
Without hugepages, high TLB miss rates would occur with the standard 4k page size, slowing performance.

Reserving Hugepages for DPDK Use
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The allocation of hugepages should be done at boot time or as soon as possible after system boot
to prevent memory from being fragmented in physical memory.
To reserve hugepages at boot time, a parameter is passed to the Linux kernel on the kernel command line.

For 2 MB pages, just pass the hugepages option to the kernel. For example, to reserve 1024 pages of 2 MB, use::

    hugepages=1024

For other hugepage sizes, for example 1G pages, the size must be specified explicitly and
can also be optionally set as the default hugepage size for the system.
For example, to reserve 4G of hugepage memory in the form of four 1G pages, the following options should be passed to the kernel::

    default_hugepagesz=1G hugepagesz=1G hugepages=4

.. note::

    The hugepage sizes that a CPU supports can be determined from the CPU flags on Intel architecture.
    If pse exists, 2M hugepages are supported; if pdpe1gb exists, 1G hugepages are supported.
    On IBM Power architecture, the supported hugepage sizes are 16MB and 16GB.

.. note::

    For 64-bit applications, it is recommended to use 1 GB hugepages if the platform supports them.

In the case of a dual-socket NUMA system,
the number of hugepages reserved at boot time is generally divided equally between the two sockets
(on the assumption that sufficient memory is present on both sockets).

See the Documentation/admin-guide/kernel-parameters.txt file in your Linux source tree for further details of these and other kernel options.

**Alternative:**

For 2 MB pages, there is also the option of allocating hugepages after the system has booted.
This is done by echoing the number of hugepages required to a nr_hugepages file in the ``/sys/devices/`` directory.
For a single-node system, the command to use is as follows (assuming that 1024 pages are required)::

    echo 1024 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages

On a NUMA machine, pages should be allocated explicitly on separate nodes::

    echo 1024 > /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
    echo 1024 > /sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages

.. note::

    For 1G pages, it is not possible to reserve the hugepage memory after the system has booted.

Using Hugepages with the DPDK
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Once the hugepage memory is reserved, to make the memory available for DPDK use, perform the following steps::

    mkdir /mnt/huge
    mount -t hugetlbfs nodev /mnt/huge

The mount point can be made permanent across reboots, by adding the following line to the ``/etc/fstab`` file::

    nodev /mnt/huge hugetlbfs defaults 0 0

For 1GB pages, the page size must be specified as a mount option::

    nodev /mnt/huge_1GB hugetlbfs pagesize=1GB 0 0
