3. Compiling the DPDK Target from Source

3.1. Install the DPDK and Browse Sources

First, uncompress the archive and move to the uncompressed DPDK source directory:

tar xJf dpdk-<version>.tar.xz
cd dpdk-<version>

The DPDK is composed of several directories:

• lib: Source code of DPDK libraries
• drivers: Source code of DPDK poll-mode drivers
• app: Source code of DPDK applications (automatic tests)
• examples: Source code of DPDK application examples
• config, buildtools, mk: Framework-related makefiles, scripts and configuration

3.2. Installation of DPDK Target Environments

The format of a DPDK target is:

ARCH-MACHINE-EXECENV-TOOLCHAIN

where:

• ARCH can be: i686, x86_64, ppc_64
• MACHINE can be: native, power8
• EXECENV can be: linuxapp, bsdapp
• TOOLCHAIN can be: gcc, icc

The targets to be installed depend on the 32-bit and/or 64-bit packages and compilers installed on the host. Available targets can be found in the DPDK/config directory. The defconfig_ prefix should not be used.

When using the Intel® C++ Compiler (icc), one of the following commands should be invoked for 64-bit or 32-bit use respectively. Notice that the shell scripts update the $PATH variable and therefore should not be performed in the same session. Also, verify the compiler’s installation directory since the path may be different:

source /opt/intel/bin/iccvars.sh intel64
source /opt/intel/bin/iccvars.sh ia32

To install and make targets, use the make install T=<target> command in the top-level DPDK directory.

For example, to compile a 64-bit target using icc, run:

make install T=x86_64-native-linuxapp-icc

To compile a 32-bit build using gcc, the make command should be:

make install T=i686-native-linuxapp-gcc

To prepare a target without building it, for example, if the configuration changes need to be made before compilation, use the make config T=<target> command:

make config T=x86_64-native-linuxapp-gcc

Once the target environment is created, the user may move to the target environment directory and continue to make code changes and re-compile. The user may also make modifications to the compile-time DPDK configuration by editing the .config file in the build directory. (This is a build-local copy of the defconfig file from the top- level config directory).

cd x86_64-native-linuxapp-gcc
vi .config
make

In addition, the make clean command can be used to remove any existing compiled files for a subsequent full, clean rebuild of the code.

3.3. Browsing the Installed DPDK Environment Target

Once a target is created it contains all libraries, including poll-mode drivers, and header files for the DPDK environment that are required to build customer applications. In addition, the test and testpmd applications are built under the build/app directory, which may be used for testing. A kmod directory is also present that contains kernel modules which may be loaded if needed.

3.4. Loading Modules to Enable Userspace IO for DPDK

To run any DPDK application, a suitable uio module can be loaded into the running kernel. In many cases, the standard uio_pci_generic module included in the Linux kernel can provide the uio capability. This module can be loaded using the command

sudo modprobe uio_pci_generic

As an alternative to the uio_pci_generic, the DPDK also includes the igb_uio module which can be found in the kmod subdirectory referred to above. It can be loaded as shown below:

sudo modprobe uio
sudo insmod kmod/igb_uio.ko

Since DPDK release 1.7 onward provides VFIO support, use of UIO is optional for platforms that support using VFIO.

3.5. Loading VFIO Module

To run an DPDK application and make use of VFIO, the vfio-pci module must be loaded:

sudo modprobe vfio-pci

Note that in order to use VFIO, your kernel must support it. VFIO kernel modules have been included in the Linux kernel since version 3.6.0 and are usually present by default, however please consult your distributions documentation to make sure that is the case.

Also, to use VFIO, both kernel and BIOS must support and be configured to use IO virtualization (such as Intel® VT-d).

For proper operation of VFIO when running DPDK applications as a non-privileged user, correct permissions should also be set up. This can be done by using the DPDK setup script (called dpdk-setup.sh and located in the usertools directory).

3.6. Binding and Unbinding Network Ports to/from the Kernel Modules

As of release 1.4, DPDK applications no longer automatically unbind all supported network ports from the kernel driver in use. Instead, all ports that are to be used by an DPDK application must be bound to the uio_pci_generic, igb_uio or vfio-pci module before the application is run. Any network ports under Linux* control will be ignored by the DPDK poll-mode drivers and cannot be used by the application.

To bind ports to the uio_pci_generic, igb_uio or vfio-pci module for DPDK use, and then subsequently return ports to Linux* control, a utility script called dpdk-devbind.py is provided in the usertools subdirectory. This utility can be used to provide a view of the current state of the network ports on the system, and to bind and unbind those ports from the different kernel modules, including the uio and vfio modules. The following are some examples of how the script can be used. A full description of the script and its parameters can be obtained by calling the script with the --help or --usage options. Note that the uio or vfio kernel modules to be used, should be loaded into the kernel before running the dpdk-devbind.py script.

To see the status of all network ports on the system:

./usertools/dpdk-devbind.py --status

Network devices using DPDK-compatible driver
============================================
0000:82:00.0 '82599EB 10-GbE NIC' drv=uio_pci_generic unused=ixgbe
0000:82:00.1 '82599EB 10-GbE NIC' drv=uio_pci_generic unused=ixgbe

Network devices using kernel driver
===================================
0000:04:00.0 'I350 1-GbE NIC' if=em0  drv=igb unused=uio_pci_generic *Active*
0000:04:00.1 'I350 1-GbE NIC' if=eth1 drv=igb unused=uio_pci_generic
0000:04:00.2 'I350 1-GbE NIC' if=eth2 drv=igb unused=uio_pci_generic
0000:04:00.3 'I350 1-GbE NIC' if=eth3 drv=igb unused=uio_pci_generic

Other network devices
=====================
<none>

To bind device eth1,``04:00.1``, to the uio_pci_generic driver:

./usertools/dpdk-devbind.py --bind=uio_pci_generic 04:00.1

or, alternatively,

./usertools/dpdk-devbind.py --bind=uio_pci_generic eth1

To restore device 82:00.0 to its original kernel binding:

./usertools/dpdk-devbind.py --bind=ixgbe 82:00.0