1 .. SPDX-License-Identifier: BSD-3-Clause
2 Copyright(c) 2010-2014 Intel Corporation.
4 Compiling and Running Sample Applications
5 =========================================
7 The chapter describes how to compile and run applications in an DPDK environment.
8 It also provides a pointer to where sample applications are stored.
12 Parts of this process can also be done using the setup script described the
13 :ref:`linux_setup_script` section of this document.
15 Compiling a Sample Application
16 ------------------------------
18 Once an DPDK target environment directory has been created (such as ``x86_64-native-linux-gcc``),
19 it contains all libraries and header files required to build an application.
21 When compiling an application in the Linux* environment on the DPDK, the following variables must be exported:
23 * ``RTE_SDK`` - Points to the DPDK installation directory.
25 * ``RTE_TARGET`` - Points to the DPDK target environment directory.
27 The following is an example of creating the ``helloworld`` application, which runs in the DPDK Linux environment.
28 This example may be found in the ``${RTE_SDK}/examples`` directory.
30 The directory contains the ``main.c`` file. This file, when combined with the libraries in the DPDK target environment,
31 calls the various functions to initialize the DPDK environment,
32 then launches an entry point (dispatch application) for each core to be utilized.
33 By default, the binary is generated in the build directory.
35 .. code-block:: console
37 cd examples/helloworld/
38 export RTE_SDK=$HOME/DPDK
39 export RTE_TARGET=x86_64-native-linux-gcc
44 INSTALL-APP helloworld
45 INSTALL-MAP helloworld.map
48 helloworld helloworld.map
52 In the above example, ``helloworld`` was in the directory structure of the DPDK.
53 However, it could have been located outside the directory structure to keep the DPDK structure intact.
54 In the following case, the ``helloworld`` application is copied to a new directory as a new starting point.
56 .. code-block:: console
58 export RTE_SDK=/home/user/DPDK
59 cp -r $(RTE_SDK)/examples/helloworld my_rte_app
61 export RTE_TARGET=x86_64-native-linux-gcc
66 INSTALL-APP helloworld
67 INSTALL-MAP helloworld.map
69 Running a Sample Application
70 ----------------------------
74 Before running the application make sure:
76 - Hugepages setup is done.
77 - Any kernel driver being used is loaded.
78 - In case needed, ports being used by the application should be
79 bound to the corresponding kernel driver.
81 refer to :ref:`linux_gsg_linux_drivers` for more details.
83 The application is linked with the DPDK target environment's Environmental Abstraction Layer (EAL) library,
84 which provides some options that are generic to every DPDK application.
86 The following is the list of options that can be given to the EAL:
88 .. code-block:: console
90 ./rte-app [-c COREMASK | -l CORELIST] [-n NUM] [-b <domain:bus:devid.func>] \
91 [--socket-mem=MB,...] [-d LIB.so|DIR] [-m MB] [-r NUM] [-v] [--file-prefix] \
92 [--proc-type <primary|secondary|auto>]
94 The EAL options are as follows:
96 * ``-c COREMASK`` or ``-l CORELIST``:
97 An hexadecimal bit mask of the cores to run on. Note that core numbering can
98 change between platforms and should be determined beforehand. The corelist is
99 a set of core numbers instead of a bitmap core mask.
102 Number of memory channels per processor socket.
104 * ``-b <domain:bus:devid.func>``:
105 Blacklisting of ports; prevent EAL from using specified PCI device
106 (multiple ``-b`` options are allowed).
109 use the specified Ethernet device(s) only. Use comma-separate
110 ``[domain:]bus:devid.func`` values. Cannot be used with ``-b`` option.
113 Memory to allocate from hugepages on specific sockets. In dynamic memory mode,
114 this memory will also be pinned (i.e. not released back to the system until
117 * ``--socket-limit``:
118 Limit maximum memory available for allocation on each socket. Does not support
122 Add a driver or driver directory to be loaded.
123 The application should use this option to load the pmd drivers
124 that are built as shared libraries.
127 Memory to allocate from hugepages, regardless of processor socket. It is
128 recommended that ``--socket-mem`` be used instead of this option.
131 Number of memory ranks.
134 Display version information on startup.
137 The directory where hugetlbfs is mounted.
139 * ``mbuf-pool-ops-name``:
140 Pool ops name for mbuf to use.
143 The prefix text used for hugepage filenames.
146 The type of process instance.
148 * ``--vmware-tsc-map``:
149 Use VMware TSC map instead of native RDTSC.
151 * ``--base-virtaddr``:
152 Specify base virtual address.
155 Specify interrupt type to be used by VFIO (has no effect if VFIO is not used).
158 Run DPDK in legacy memory mode (disable memory reserve/unreserve at runtime,
159 but provide more IOVA-contiguous memory).
161 * ``--single-file-segments``:
162 Store memory segments in fewer files (dynamic memory mode only - does not
163 affect legacy memory mode).
165 The ``-c`` or ``-l`` and option is mandatory; the others are optional.
167 Copy the DPDK application binary to your target, then run the application as follows
168 (assuming the platform has four memory channels per processor socket,
169 and that cores 0-3 are present and are to be used for running the application)::
171 ./helloworld -l 0-3 -n 4
175 The ``--proc-type`` and ``--file-prefix`` EAL options are used for running
176 multiple DPDK processes. See the "Multi-process Sample Application"
177 chapter in the *DPDK Sample Applications User Guide* and the *DPDK
178 Programmers Guide* for more details.
180 Logical Core Use by Applications
181 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
183 The coremask (-c 0x0f) or corelist (-l 0-3) parameter is always mandatory for DPDK applications.
184 Each bit of the mask corresponds to the equivalent logical core number as reported by Linux. The preferred corelist option is a cleaner method to define cores to be used.
185 Since these logical core numbers, and their mapping to specific cores on specific NUMA sockets, can vary from platform to platform,
186 it is recommended that the core layout for each platform be considered when choosing the coremask/corelist to use in each case.
188 On initialization of the EAL layer by an DPDK application, the logical cores to be used and their socket location are displayed.
189 This information can also be determined for all cores on the system by examining the ``/proc/cpuinfo`` file, for example, by running cat ``/proc/cpuinfo``.
190 The physical id attribute listed for each processor indicates the CPU socket to which it belongs.
191 This can be useful when using other processors to understand the mapping of the logical cores to the sockets.
195 A more graphical view of the logical core layout may be obtained using the ``lstopo`` Linux utility.
196 On Fedora Linux, this may be installed and run using the following command::
198 sudo yum install hwloc
203 The logical core layout can change between different board layouts and should be checked before selecting an application coremask/corelist.
205 Hugepage Memory Use by Applications
206 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
208 When running an application, it is recommended to use the same amount of memory as that allocated for hugepages.
209 This is done automatically by the DPDK application at startup,
210 if no ``-m`` or ``--socket-mem`` parameter is passed to it when run.
212 If more memory is requested by explicitly passing a ``-m`` or ``--socket-mem`` value, the application fails.
213 However, the application itself can also fail if the user requests less memory than the reserved amount of hugepage-memory, particularly if using the ``-m`` option.
214 The reason is as follows.
215 Suppose the system has 1024 reserved 2 MB pages in socket 0 and 1024 in socket 1.
216 If the user requests 128 MB of memory, the 64 pages may not match the constraints:
218 * The hugepage memory by be given to the application by the kernel in socket 1 only.
219 In this case, if the application attempts to create an object, such as a ring or memory pool in socket 0, it fails.
220 To avoid this issue, it is recommended that the ``--socket-mem`` option be used instead of the ``-m`` option.
222 * These pages can be located anywhere in physical memory, and, although the DPDK EAL will attempt to allocate memory in contiguous blocks,
223 it is possible that the pages will not be contiguous. In this case, the application is not able to allocate big memory pools.
225 The socket-mem option can be used to request specific amounts of memory for specific sockets.
226 This is accomplished by supplying the ``--socket-mem`` flag followed by amounts of memory requested on each socket,
227 for example, supply ``--socket-mem=0,512`` to try and reserve 512 MB for socket 1 only.
228 Similarly, on a four socket system, to allocate 1 GB memory on each of sockets 0 and 2 only, the parameter ``--socket-mem=1024,0,1024`` can be used.
229 No memory will be reserved on any CPU socket that is not explicitly referenced, for example, socket 3 in this case.
230 If the DPDK cannot allocate enough memory on each socket, the EAL initialization fails.
232 Additional Sample Applications
233 ------------------------------
235 Additional sample applications are included in the ${RTE_SDK}/examples directory.
236 These sample applications may be built and run in a manner similar to that described in earlier sections in this manual.
237 In addition, see the *DPDK Sample Applications User Guide* for a description of the application,
238 specific instructions on compilation and execution and some explanation of the code.
240 Additional Test Applications
241 ----------------------------
243 In addition, there are two other applications that are built when the libraries are created.
244 The source files for these are in the DPDK/app directory and are called test and testpmd.
245 Once the libraries are created, they can be found in the build/app directory.
247 * The test application provides a variety of specific tests for the various functions in the DPDK.
249 * The testpmd application provides a number of different packet throughput tests and
250 examples of features such as how to use the Flow Director found in the IntelĀ® 82599 10 Gigabit Ethernet Controller.