3. Compiling the DPDK Target from Source

3.1. Uncompress 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: Framework-related scripts and configuration

3.2. Compiling and Installing DPDK System-wide

DPDK can be configured, built and installed on your system using the tools meson and ninja.

3.2.1. DPDK Configuration

To configure a DPDK build use:

meson setup <options> build

where “build” is the desired output build directory, and “<options>” can be empty or one of a number of meson or DPDK-specific build options, described later in this section. The configuration process will finish with a summary of what DPDK libraries and drivers are to be built and installed, and for each item disabled, a reason why that is the case. This information can be used, for example, to identify any missing required packages for a driver.

Once configured, to build and then install DPDK system-wide use:

cd build
ninja
ninja install
ldconfig

The last two commands above generally need to be run as root, with the ninja install step copying the built objects to their final system-wide locations, and the last step causing the dynamic loader ld.so to update its cache to take account of the new objects.

Note

On some linux distributions, such as Fedora or Redhat, paths in /usr/local are not in the default paths for the loader. Therefore, on these distributions, /usr/local/lib and /usr/local/lib64 should be added to a file in /etc/ld.so.conf.d/ before running ldconfig.

3.2.2. Adjusting Build Options

DPDK has a number of options that can be adjusted as part of the build configuration process. These options can be listed by running meson configure inside a configured build folder. Many of these options come from the “meson” tool itself and can be seen documented on the Meson Website.

For example, to change the build-type from the default, “debugoptimized”, to a regular “debug” build, you can either:

  • pass -Dbuildtype=debug or --buildtype=debug to meson when configuring the build folder initially
  • run meson configure -Dbuildtype=debug inside the build folder after the initial meson run.

Other options are specific to the DPDK project but can be adjusted similarly. The “platform” option specifies a set a configuration parameters that will be used. The valid values are:

  • -Dplatform=native will tailor the configuration to the build machine.
  • -Dplatform=generic will use configuration that works on all machines of the same architecture as the build machine.
  • -Dplatform=<SoC> will use configuration optimized for a particular SoC. Consult the “socs” dictionary in config/arm/meson.build to see which SoCs are supported.

The instruction set will be set automatically by default according to these rules:

  • -Dplatform=native sets cpu_instruction_set to native, which configures -march (x86_64), -mcpu (ppc), -mtune (ppc) to native.
  • -Dplatform=generic sets cpu_instruction_set to generic, which configures -march (x86_64), -mcpu (ppc), -mtune (ppc) to a common minimal baseline needed for DPDK.

To override what instruction set will be used, set the cpu_instruction_set parameter to the instruction set of your choice (such as corei7, power8, etc.).

cpu_instruction_set is not used in Arm builds, as setting the instruction set without other parameters leads to inferior builds. The way to tailor Arm builds is to build for a SoC using -Dplatform=<SoC> mentioned above.

The values determined by the platform parameter may be overwritten. For example, to set the max_lcores value to 256, you can either:

  • pass -Dmax_lcores=256 to meson when configuring the build folder initially
  • run meson configure -Dmax_lcores=256 inside the build folder after the initial meson run.

Some of the DPDK sample applications in the examples directory can be automatically built as part of a meson build too. To do so, pass a comma-separated list of the examples to build to the -Dexamples meson option as below:

meson setup -Dexamples=l2fwd,l3fwd build

As with other meson options, this can also be set post-initial-config using meson configure in the build directory. There is also a special value “all” to request that all example applications whose dependencies are met on the current system are built. When -Dexamples=all is set as a meson option, meson will check each example application to see if it can be built, and add all which can be built to the list of tasks in the ninja build configuration file.

3.2.3. Building 32-bit DPDK on 64-bit Systems

To build a 32-bit copy of DPDK on a 64-bit OS, the -m32 flag should be passed to the compiler and linker to force the generation of 32-bit objects and binaries. This can be done either by setting CFLAGS and LDFLAGS in the environment, or by passing the value to meson using -Dc_args=-m32 and -Dc_link_args=-m32. For correctly identifying and using any dependency packages, the pkg-config tool must also be configured to look in the appropriate directory for .pc files for 32-bit libraries. This is done by setting PKG_CONFIG_LIBDIR to the appropriate path.

The following meson command can be used on RHEL/Fedora systems to configure a 32-bit build, assuming the relevant 32-bit development packages, such as a 32-bit libc, are installed:

PKG_CONFIG_LIBDIR=/usr/lib/pkgconfig \
    meson setup -Dc_args='-m32' -Dc_link_args='-m32' build

For Debian/Ubuntu systems, the equivalent command is:

PKG_CONFIG_LIBDIR=/usr/lib/i386-linux-gnu/pkgconfig \
    meson setup -Dc_args='-m32' -Dc_link_args='-m32' build

Once the build directory has been configured, DPDK can be compiled using ninja as described above.

3.2.4. Building Applications Using Installed DPDK

When installed system-wide, DPDK provides a pkg-config file libdpdk.pc for applications to query as part of their build. It’s recommended that the pkg-config file be used, rather than hard-coding the parameters (cflags/ldflags) for DPDK into the application build process.

An example of how to query and use the pkg-config file can be found in the Makefile of each of the example applications included with DPDK. A simplified example snippet is shown below, where the target binary name has been stored in the variable $(APP) and the sources for that build are stored in $(SRCS-y).

PKGCONF = pkg-config

CFLAGS += -O3 $(shell $(PKGCONF) --cflags libdpdk)
LDFLAGS += $(shell $(PKGCONF) --libs libdpdk)

$(APP): $(SRCS-y) Makefile
        $(CC) $(CFLAGS) $(SRCS-y) -o $@ $(LDFLAGS)

Note

Unlike with the make build system present in older DPDK releases, the meson system is not designed to be used directly from a build directory. Instead it is recommended that it be installed either system-wide or to a known location in the user’s home directory. The install location can be set using the –prefix meson option (default: /usr/local).

an equivalent build recipe for a simple DPDK application using meson as a build system is shown below:

project('dpdk-app', 'c')

dpdk = dependency('libdpdk')
sources = files('main.c')
executable('dpdk-app', sources, dependencies: dpdk)