3. Compiling the DPDK Target from Source¶
Parts of this process can also be done using the setup script described in Chapter 6 of this document.
3.1. Install the DPDK and Browse Sources¶
First, uncompress the archive and move to the uncompressed DPDK source directory:
user@host:~$ unzip DPDK-<version>.zip
user@host:~$ cd DPDK-<version>
app/ config/ examples/ lib/ LICENSE.GPL LICENSE.LGPL Makefile mk/ scripts/ tools/
The DPDK is composed of several directories:
- lib: Source code of DPDK libraries
- app: Source code of DPDK applications (automatic tests)
- examples: Source code of DPDK application examples
- config, tools, scripts, mk: Framework-related makefiles, scripts and configuration
3.2. Installation of DPDK Target Environments¶
The format of a DPDK target is:
- ARCH can be: i686, x86_64, ppc_64
- MACHINE can be: native, ivshmem, 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.
Configuration files are provided with the RTE_MACHINE optimization level set. Within the configuration files, the RTE_MACHINE configuration value is set to native, which means that the compiled software is tuned for the platform on which it is built. For more information on this setting, and its possible values, see the DPDK Programmers Guide.
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 compile all 64-bit targets using gcc, use:
make install T=x86_64*gcc
To compile all 64-bit targets using both gcc and icc, use:
make install T=x86_64-*
The wildcard operator (*) can be used to create multiple targets at the same time.
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
The igb_uio module must be compiled with the same kernel as the one running on the target. If the DPDK is not being built on the target machine, the RTE_KERNELDIR environment variable should be used to point the compilation at a copy of the kernel version to be used on the target machine.
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).
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 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. In the case of Linux, a kmod directory is also present that contains a module to install:
$ ls x86_64-native-linuxapp-gcc
app build hostapp include kmod lib Makefile
3.4. Loading the DPDK igb_uio Module¶
To run any DPDK application, the igb_uio module can be loaded into the running kernel. The module is found in the kmod sub-directory of the DPDK target directory. This module should be loaded using the insmod command as shown below (assuming that the current directory is the DPDK target directory). In many cases, the uio support in the Linux* kernel is compiled as a module rather than as part of the kernel, so it is often necessary to load the uio module first:
sudo modprobe uio
sudo insmod kmod/igb_uio.ko
Since DPDK release 1.7 provides VFIO support, compilation and use of igb_uio module has become 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 setup.sh and located in the tools directory).
3.6. Binding and Unbinding Network Ports to/from the igb_uioor VFIO 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 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.
The DPDK will, by default, no longer automatically unbind network ports from the kernel driver at startup. Any ports to be used by an DPDK application must be unbound from Linux* control and bound to the igb_uio or vfio-pci module before the application is run.
To bind ports to the igb_uio or vfio-pci module for DPDK use, and then subsequently return ports to Linux* control, a utility script called dpdk_nic _bind.py is provided in the tools 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 igb_uio and vfio-pci. 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.
Due to the way VFIO works, there are certain limitations to which devices can be used with VFIO. Mainly it comes down to how IOMMU groups work. Any Virtual Function device can be used with VFIO on its own, but physical devices will require either all ports bound to VFIO, or some of them bound to VFIO while others not being bound to anything at all.
If your device is behind a PCI-to-PCI bridge, the bridge will then be part of the IOMMU group in which your device is in. Therefore, the bridge driver should also be unbound from the bridge PCI device for VFIO to work with devices behind the bridge.
While any user can run the dpdk_nic_bind.py script to view the status of the network ports, binding or unbinding network ports requires root privileges.
To see the status of all network ports on the system:
root@host:DPDK# ./tools/dpdk_nic_bind.py --status
Network devices using IGB_UIO driver
0000:82:00.0 '82599EB 10-Gigabit SFI/SFP+ Network Connection' drv=igb_uio unused=ixgbe
0000:82:00.1 '82599EB 10-Gigabit SFI/SFP+ Network Connection' drv=igb_uio unused=ixgbe
Network devices using kernel driver
0000:04:00.0 'I350 Gigabit Network Connection' if=em0 drv=igb unused=igb_uio *Active*
0000:04:00.1 'I350 Gigabit Network Connection' if=eth1 drv=igb unused=igb_uio
0000:04:00.2 'I350 Gigabit Network Connection' if=eth2 drv=igb unused=igb_uio
0000:04:00.3 'I350 Gigabit Network Connection' if=eth3 drv=igb unused=igb_uio
Other network devices
To bind device eth1, 04:00.1, to the igb_uio driver:
root@host:DPDK# ./tools/dpdk_nic_bind.py --bind=igb_uio 04:00.1
root@host:DPDK# ./tools/dpdk_nic_bind.py --bind=igb_uio eth1
To restore device 82:00.0 to its original kernel binding:
root@host:DPDK# ./tools/dpdk_nic_bind.py --bind=ixgbe 82:00.0