xref: /dpdk/doc/guides/linux_gsg/build_sample_apps.rst (revision d0a6a32687cf12bc97ae26b6a3d2ce14e44aa2a5)
1..  BSD LICENSE
2    Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
3    All rights reserved.
4
5    Redistribution and use in source and binary forms, with or without
6    modification, are permitted provided that the following conditions
7    are met:
8
9    * Redistributions of source code must retain the above copyright
10    notice, this list of conditions and the following disclaimer.
11    * Redistributions in binary form must reproduce the above copyright
12    notice, this list of conditions and the following disclaimer in
13    the documentation and/or other materials provided with the
14    distribution.
15    * Neither the name of Intel Corporation nor the names of its
16    contributors may be used to endorse or promote products derived
17    from this software without specific prior written permission.
18
19    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31Compiling and Running Sample Applications
32=========================================
33
34The chapter describes how to compile and run applications in an DPDK environment.
35It also provides a pointer to where sample applications are stored.
36
37.. note::
38
39    Parts of this process can also be done using the setup script described the
40    :ref:`linux_setup_script` section of this document.
41
42Compiling a Sample Application
43------------------------------
44
45Once an DPDK target environment directory has been created (such as ``x86_64-native-linuxapp-gcc``),
46it contains all libraries and header files required to build an application.
47
48When compiling an application in the Linux* environment on the DPDK, the following variables must be exported:
49
50* ``RTE_SDK`` - Points to the DPDK installation directory.
51
52* ``RTE_TARGET`` - Points to the DPDK target environment directory.
53
54The following is an example of creating the ``helloworld`` application, which runs in the DPDK Linux environment.
55This example may be found in the ``${RTE_SDK}/examples`` directory.
56
57The directory contains the ``main.c`` file. This file, when combined with the libraries in the DPDK target environment,
58calls the various functions to initialize the DPDK environment,
59then launches an entry point (dispatch application) for each core to be utilized.
60By default, the binary is generated in the build directory.
61
62.. code-block:: console
63
64    cd examples/helloworld/
65    export RTE_SDK=$HOME/DPDK
66    export RTE_TARGET=x86_64-native-linuxapp-gcc
67
68    make
69        CC main.o
70        LD helloworld
71        INSTALL-APP helloworld
72        INSTALL-MAP helloworld.map
73
74    ls build/app
75        helloworld helloworld.map
76
77.. note::
78
79    In the above example, ``helloworld`` was in the directory structure of the DPDK.
80    However, it could have been located outside the directory structure to keep the DPDK structure intact.
81    In the following case, the ``helloworld`` application is copied to a new directory as a new starting point.
82
83    .. code-block:: console
84
85       export RTE_SDK=/home/user/DPDK
86       cp -r $(RTE_SDK)/examples/helloworld my_rte_app
87       cd my_rte_app/
88       export RTE_TARGET=x86_64-native-linuxapp-gcc
89
90       make
91         CC main.o
92         LD helloworld
93         INSTALL-APP helloworld
94         INSTALL-MAP helloworld.map
95
96Running a Sample Application
97----------------------------
98
99.. warning::
100
101    The UIO drivers and hugepages must be setup prior to running an application.
102
103.. warning::
104
105    Any ports to be used by the application must be already bound to an appropriate kernel
106    module, as described in :ref:`linux_gsg_binding_kernel`, prior to running the application.
107
108The application is linked with the DPDK target environment's Environmental Abstraction Layer (EAL) library,
109which provides some options that are generic to every DPDK application.
110
111The following is the list of options that can be given to the EAL:
112
113.. code-block:: console
114
115    ./rte-app -c COREMASK [-n NUM] [-b <domain:bus:devid.func>] \
116              [--socket-mem=MB,...] [-m MB] [-r NUM] [-v] [--file-prefix] \
117	      [--proc-type <primary|secondary|auto>] [-- xen-dom0]
118
119The EAL options are as follows:
120
121* ``-c COREMASK``:
122  An hexadecimal bit mask of the cores to run on. Note that core numbering can
123  change between platforms and should be determined beforehand.
124
125* ``-n NUM``:
126  Number of memory channels per processor socket.
127
128* ``-b <domain:bus:devid.func>``:
129  Blacklisting of ports; prevent EAL from using specified PCI device
130  (multiple ``-b`` options are allowed).
131
132* ``--use-device``:
133  use the specified Ethernet device(s) only. Use comma-separate
134  ``[domain:]bus:devid.func`` values. Cannot be used with ``-b`` option.
135
136* ``--socket-mem``:
137  Memory to allocate from hugepages on specific sockets.
138
139* ``-m MB``:
140  Memory to allocate from hugepages, regardless of processor socket. It is
141  recommended that ``--socket-mem`` be used instead of this option.
142
143* ``-r NUM``:
144  Number of memory ranks.
145
146* ``-v``:
147  Display version information on startup.
148
149* ``--huge-dir``:
150  The directory where hugetlbfs is mounted.
151
152* ``--file-prefix``:
153  The prefix text used for hugepage filenames.
154
155* ``--proc-type``:
156  The type of process instance.
157
158* ``--xen-dom0``:
159  Support application running on Xen Domain0 without hugetlbfs.
160
161* ``--vmware-tsc-map``:
162  Use VMware TSC map instead of native RDTSC.
163
164* ``--base-virtaddr``:
165  Specify base virtual address.
166
167* ``--vfio-intr``:
168  Specify interrupt type to be used by VFIO (has no effect if VFIO is not used).
169
170The ``-c`` and option is mandatory; the others are optional.
171
172Copy the DPDK application binary to your target, then run the application as follows
173(assuming the platform has four memory channels per processor socket,
174and that cores 0-3 are present and are to be used for running the application)::
175
176    ./helloworld -c f -n 4
177
178.. note::
179
180    The ``--proc-type`` and ``--file-prefix`` EAL options are used for running
181    multiple DPDK processes. See the "Multi-process Sample Application"
182    chapter in the *DPDK Sample Applications User Guide* and the *DPDK
183    Programmers Guide* for more details.
184
185Logical Core Use by Applications
186~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
187
188The coremask parameter is always mandatory for DPDK applications.
189Each bit of the mask corresponds to the equivalent logical core number as reported by Linux.
190Since these logical core numbers, and their mapping to specific cores on specific NUMA sockets, can vary from platform to platform,
191it is recommended that the core layout for each platform be considered when choosing the coremask to use in each case.
192
193On initialization of the EAL layer by an DPDK application, the logical cores to be used and their socket location are displayed.
194This information can also be determined for all cores on the system by examining the ``/proc/cpuinfo`` file, for example, by running cat ``/proc/cpuinfo``.
195The physical id attribute listed for each processor indicates the CPU socket to which it belongs.
196This can be useful when using other processors to understand the mapping of the logical cores to the sockets.
197
198.. note::
199
200    A more graphical view of the logical core layout may be obtained using the ``lstopo`` Linux utility.
201    On Fedora Linux, this may be installed and run using the following command::
202
203        sudo yum install hwloc
204        ./lstopo
205
206.. warning::
207
208    The logical core layout can change between different board layouts and should be checked before selecting an application coremask.
209
210Hugepage Memory Use by Applications
211~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
212
213When running an application, it is recommended to use the same amount of memory as that allocated for hugepages.
214This is done automatically by the DPDK application at startup,
215if no ``-m`` or ``--socket-mem`` parameter is passed to it when run.
216
217If more memory is requested by explicitly passing a ``-m`` or ``--socket-mem`` value, the application fails.
218However, 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.
219The reason is as follows.
220Suppose the system has 1024 reserved 2 MB pages in socket 0 and 1024 in socket 1.
221If the user requests 128 MB of memory, the 64 pages may not match the constraints:
222
223*   The hugepage memory by be given to the application by the kernel in socket 1 only.
224    In this case, if the application attempts to create an object, such as a ring or memory pool in socket 0, it fails.
225    To avoid this issue, it is recommended that the ``--socket-mem`` option be used instead of the ``-m`` option.
226
227*   These pages can be located anywhere in physical memory, and, although the DPDK EAL will attempt to allocate memory in contiguous blocks,
228    it is possible that the pages will not be contiguous. In this case, the application is not able to allocate big memory pools.
229
230The socket-mem option can be used to request specific amounts of memory for specific sockets.
231This is accomplished by supplying the ``--socket-mem`` flag followed by amounts of memory requested on each socket,
232for example, supply ``--socket-mem=0,512`` to try and reserve 512 MB for socket 1 only.
233Similarly, 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.
234No memory will be reserved on any CPU socket that is not explicitly referenced, for example, socket 3 in this case.
235If the DPDK cannot allocate enough memory on each socket, the EAL initialization fails.
236
237Additional Sample Applications
238------------------------------
239
240Additional sample applications are included in the ${RTE_SDK}/examples directory.
241These sample applications may be built and run in a manner similar to that described in earlier sections in this manual.
242In addition, see the *DPDK Sample Applications User Guide* for a description of the application,
243specific instructions on compilation and execution and some explanation of the code.
244
245Additional Test Applications
246----------------------------
247
248In addition, there are two other applications that are built when the libraries are created.
249The source files for these are in the DPDK/app directory and are called test and testpmd.
250Once the libraries are created, they can be found in the build/app directory.
251
252*   The test application provides a variety of specific tests for the various functions in the DPDK.
253
254*   The testpmd application provides a number of different packet throughput tests and
255    examples of features such as how to use the Flow Director found in the Intel® 82599 10 Gigabit Ethernet Controller.
256