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diff --git a/doc/build-sdk-meson.txt b/doc/build-sdk-meson.txt new file mode 100644 index 00000000..9618e759 --- /dev/null +++ b/doc/build-sdk-meson.txt @@ -0,0 +1,203 @@ +INSTALLING DPDK USING THE MESON BUILD SYSTEM +--------------------------------------------- + +NOTE: Compiling and installing DPDK using ``meson`` and ``ninja``, rather +than using ``make`` (GNU make) is EXPERIMENTAL. Official builds of DPDK +should always be done using ``make``, as described in the ``Getting Started +Guide`` documentation, and at "http://dpdk.org/doc/quick-start". + +Summary +-------- +For many platforms, compiling and installing DPDK should work using the +following set of commands:: + + meson build + cd build + ninja + ninja install + +This will compile DPDK in the ``build`` subdirectory, and then install the +resulting libraries, drivers and header files onto the system - generally +in /usr/local. A package-config file, ``libdpdk.pc``, for DPDK will also +be installed to allow ease of compiling and linking with applications. + +After installation, to use DPDK, the necessary CFLAG and LDFLAG variables +can be got from pkg-config:: + + pkg-config --cflags libdpdk + pkg-config --libs libdpdk + +More detail on each of these steps can be got from the following sections. + + +Getting the Tools +------------------ + +The ``meson`` tool is used to configure a DPDK build. On most Linux +distributions this can be got using the local package management system, +e.g. ``dnf install meson`` or ``apt-get install meson``. If meson is not +available as a suitable package, it can also be installed using the Python +3 ``pip`` tool, e.g. ``pip3 install meson``. Version 0.42 of meson is +recommended - if the version packaged is too old, the latest version is +generally available from "pip". + +The other dependency for building is the ``ninja`` tool, which acts similar +to make and performs the actual build using information provided by meson. +Installing meson will, in many cases, also install ninja, but, if not +already installed, it too is generally packaged by most Linux distributions. +If not available as a package, it can be downloaded as source or binary from +https://ninja-build.org/ + + +Configuring the Build +---------------------- + +To configure a build, run the meson tool, passing the path to the directory +to be used for the build e.g. ``meson build``, as shown above. If calling +meson from somewhere other than the root directory of the DPDK project the +path to the root directory should be passed as the first parameter, and the +build path as the second. For example, to build DPDK in /tmp/dpdk-build:: + + user@host:/tmp$ meson ~user/dpdk dpdk-build + +Meson will then configure the build based on settings in the project's +meson.build files, and by checking the build environment for e.g. compiler +properties or the presence of dependencies, such as libpcap, or openssl +libcrypto libraries. Once done, meson writes a ``build.ninja`` file in the +build directory to be used to do the build itself when ninja is called. + +Tuning of the build is possible, both as part of the original meson call, +or subsequently using ``meson configure`` command (``mesonconf`` in some +older versions). Some options, such as ``buildtype``, or ``werror`` are +built into meson, while others, such as ``max_lcores``, or the list of +examples to build, are DPDK-specific. To have a list of all options +available run ``meson configure`` in the build directory. + +Examples of adjusting the defaults when doing initial meson configuration. +Project-specific options are passed used -Doption=value:: + + meson --werror werrorbuild # build with warnings as errors + + meson --buildtype=debug debugbuild # build for debugging + + meson -Dexamples=l3fwd,l2fwd fwdbuild # build some examples as + # part of the normal DPDK build + + meson -Dmax_lcores=8 smallbuild # scale build for smaller systems + +Examples of setting the same options using meson configure:: + + meson configure -Dwerror=true + + meson configure -Dbuildtype=debug + + meson configure -Dexamples=l3fwd,l2fwd + + meson configure -Dmax_lcores=8 + +NOTE: once meson has been run to configure a build in a directory, it +cannot be run again on the same directory. Instead ``meson configure`` +should be used to change the build settings within the directory, and when +``ninja`` is called to do the build itself, it will trigger the necessary +re-scan from meson. + +As well as those settings taken from ``meson configure``, other options +such as the compiler to use can be passed via environment variables. For +example:: + + CC=clang meson clang-build + +NOTE: for more comprehensive overriding of compilers or other environment +settings, the tools for cross-compilation may be considered. However, for +basic overriding of the compiler etc., the above form works as expected. + + +Performing the Build +--------------------- + +Use ``ninja`` to perform the actual build inside the build folder +previously configured. In most cases no arguments are necessary. + +Ninja accepts a number of flags which are similar to make. For example, to +call ninja from outside the build folder, you can use ``ninja -C build``. +Ninja also runs parallel builds by default, but you can limit this using +the ``-j`` flag, e.g. ``ninja -j1 -v`` to do the build one step at a time, +printing each command on a new line as it runs. + + +Installing the Compiled Files +------------------------------ + +Use ``ninja install`` to install the required DPDK files onto the system. +The install prefix defaults to ``/usr/local`` but can be used as with other +options above. The environment variable ``DEST_DIR`` can be used to adjust +the root directory for the install, for example when packaging. + +With the base install directory, the individual directories for libraries +and headers are configurable. By default, the following will be the +installed layout:: + + headers -> /usr/local/include + libraries -> /usr/local/lib64 + drivers -> /usr/local/lib64/dpdk/drivers + libdpdk.pc -> /usr/local/lib64/pkgconfig + +For the drivers, these will also be symbolically linked into the library +install directory, so that ld.so can find them in cases where one driver may +depend on another, e.g. a NIC PMD depending upon the PCI bus driver. Within +the EAL, the default search path for drivers will be set to the configured +driver install path, so dynamically-linked applications can be run without +having to pass in ``-d /path/to/driver`` options for standard drivers. + + +Cross Compiling DPDK +-------------------- + +To cross-compile DPDK on a desired target machine we can use the following +command:: + + meson cross-build --cross-file <target_machine_configuration> + +For example if the target machine is arm64 we can use the following +command:: + meson arm-build --cross-file config/arm/arm64_armv8_linuxapp_gcc + +where config/arm/arm64_armv8_linuxapp_gcc contains the following +parameters:: + + [binaries] + c = 'aarch64-linux-gnu-gcc' + cpp = 'aarch64-linux-gnu-cpp' + ar = 'aarch64-linux-gnu-ar' + + [host_machine] + system = 'linux' + cpu_family = 'aarch64' + cpu = 'armv8-a' + endian = 'little' + + +Using the DPDK within an Application +------------------------------------- + +To compile and link against DPDK within an application, pkg-config should +be used to query the correct parameters. Examples of this are given in the +makefiles for the example applications included with DPDK. They demonstrate +how to link either against the DPDK shared libraries, or against the static +versions of the same. + +From examples/helloworld/Makefile:: + + PC_FILE := $(shell pkg-config --path libdpdk) + CFLAGS += -O3 $(shell pkg-config --cflags libdpdk) + LDFLAGS_SHARED = $(shell pkg-config --libs libdpdk) + LDFLAGS_STATIC = -Wl,-Bstatic $(shell pkg-config --static --libs libdpdk) + + build/$(APP)-shared: $(SRCS-y) Makefile $(PC_FILE) | build + $(CC) $(CFLAGS) $(SRCS-y) -o $@ $(LDFLAGS) $(LDFLAGS_SHARED) + + build/$(APP)-static: $(SRCS-y) Makefile $(PC_FILE) | build + $(CC) $(CFLAGS) $(SRCS-y) -o $@ $(LDFLAGS) $(LDFLAGS_STATIC) + + build: + @mkdir -p $@ |