1.. SPDX-License-Identifier: BSD-3-Clause 2 Copyright(c) 2010-2014 Intel Corporation. 3 4Compiling and Running Sample Applications 5========================================= 6 7The chapter describes how to compile and run applications in an DPDK environment. 8It also provides a pointer to where sample applications are stored. 9 10.. note:: 11 12 Parts of this process can also be done using the setup script described the 13 :ref:`linux_setup_script` section of this document. 14 15Compiling a Sample Application 16------------------------------ 17 18Once an DPDK target environment directory has been created (such as ``x86_64-native-linuxapp-gcc``), 19it contains all libraries and header files required to build an application. 20 21When compiling an application in the Linux* environment on the DPDK, the following variables must be exported: 22 23* ``RTE_SDK`` - Points to the DPDK installation directory. 24 25* ``RTE_TARGET`` - Points to the DPDK target environment directory. 26 27The following is an example of creating the ``helloworld`` application, which runs in the DPDK Linux environment. 28This example may be found in the ``${RTE_SDK}/examples`` directory. 29 30The directory contains the ``main.c`` file. This file, when combined with the libraries in the DPDK target environment, 31calls the various functions to initialize the DPDK environment, 32then launches an entry point (dispatch application) for each core to be utilized. 33By default, the binary is generated in the build directory. 34 35.. code-block:: console 36 37 cd examples/helloworld/ 38 export RTE_SDK=$HOME/DPDK 39 export RTE_TARGET=x86_64-native-linuxapp-gcc 40 41 make 42 CC main.o 43 LD helloworld 44 INSTALL-APP helloworld 45 INSTALL-MAP helloworld.map 46 47 ls build/app 48 helloworld helloworld.map 49 50.. note:: 51 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. 55 56 .. code-block:: console 57 58 export RTE_SDK=/home/user/DPDK 59 cp -r $(RTE_SDK)/examples/helloworld my_rte_app 60 cd my_rte_app/ 61 export RTE_TARGET=x86_64-native-linuxapp-gcc 62 63 make 64 CC main.o 65 LD helloworld 66 INSTALL-APP helloworld 67 INSTALL-MAP helloworld.map 68 69Running a Sample Application 70---------------------------- 71 72.. warning:: 73 74 Before running the application make sure: 75 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. 80 81 refer to :ref:`linux_gsg_linux_drivers` for more details. 82 83The application is linked with the DPDK target environment's Environmental Abstraction Layer (EAL) library, 84which provides some options that are generic to every DPDK application. 85 86The following is the list of options that can be given to the EAL: 87 88.. code-block:: console 89 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>] 93 94The EAL options are as follows: 95 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. 100 101* ``-n NUM``: 102 Number of memory channels per processor socket. 103 104* ``-b <domain:bus:devid.func>``: 105 Blacklisting of ports; prevent EAL from using specified PCI device 106 (multiple ``-b`` options are allowed). 107 108* ``--use-device``: 109 use the specified Ethernet device(s) only. Use comma-separate 110 ``[domain:]bus:devid.func`` values. Cannot be used with ``-b`` option. 111 112* ``--socket-mem``: 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 115 application closes). 116 117* ``-d``: 118 Add a driver or driver directory to be loaded. 119 The application should use this option to load the pmd drivers 120 that are built as shared libraries. 121 122* ``-m MB``: 123 Memory to allocate from hugepages, regardless of processor socket. It is 124 recommended that ``--socket-mem`` be used instead of this option. 125 126* ``-r NUM``: 127 Number of memory ranks. 128 129* ``-v``: 130 Display version information on startup. 131 132* ``--huge-dir``: 133 The directory where hugetlbfs is mounted. 134 135* ``mbuf-pool-ops-name``: 136 Pool ops name for mbuf to use. 137 138* ``--file-prefix``: 139 The prefix text used for hugepage filenames. 140 141* ``--proc-type``: 142 The type of process instance. 143 144* ``--vmware-tsc-map``: 145 Use VMware TSC map instead of native RDTSC. 146 147* ``--base-virtaddr``: 148 Specify base virtual address. 149 150* ``--vfio-intr``: 151 Specify interrupt type to be used by VFIO (has no effect if VFIO is not used). 152 153* ``--legacy-mem``: 154 Run DPDK in legacy memory mode (disable memory reserve/unreserve at runtime, 155 but provide more IOVA-contiguous memory). 156 157* ``--single-file-segments``: 158 Store memory segments in fewer files (dynamic memory mode only - does not 159 affect legacy memory mode). 160 161The ``-c`` or ``-l`` and option is mandatory; the others are optional. 162 163Copy the DPDK application binary to your target, then run the application as follows 164(assuming the platform has four memory channels per processor socket, 165and that cores 0-3 are present and are to be used for running the application):: 166 167 ./helloworld -l 0-3 -n 4 168 169.. note:: 170 171 The ``--proc-type`` and ``--file-prefix`` EAL options are used for running 172 multiple DPDK processes. See the "Multi-process Sample Application" 173 chapter in the *DPDK Sample Applications User Guide* and the *DPDK 174 Programmers Guide* for more details. 175 176Logical Core Use by Applications 177~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 178 179The coremask (-c 0x0f) or corelist (-l 0-3) parameter is always mandatory for DPDK applications. 180Each 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. 181Since these logical core numbers, and their mapping to specific cores on specific NUMA sockets, can vary from platform to platform, 182it is recommended that the core layout for each platform be considered when choosing the coremask/corelist to use in each case. 183 184On initialization of the EAL layer by an DPDK application, the logical cores to be used and their socket location are displayed. 185This information can also be determined for all cores on the system by examining the ``/proc/cpuinfo`` file, for example, by running cat ``/proc/cpuinfo``. 186The physical id attribute listed for each processor indicates the CPU socket to which it belongs. 187This can be useful when using other processors to understand the mapping of the logical cores to the sockets. 188 189.. note:: 190 191 A more graphical view of the logical core layout may be obtained using the ``lstopo`` Linux utility. 192 On Fedora Linux, this may be installed and run using the following command:: 193 194 sudo yum install hwloc 195 ./lstopo 196 197.. warning:: 198 199 The logical core layout can change between different board layouts and should be checked before selecting an application coremask/corelist. 200 201Hugepage Memory Use by Applications 202~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 203 204When running an application, it is recommended to use the same amount of memory as that allocated for hugepages. 205This is done automatically by the DPDK application at startup, 206if no ``-m`` or ``--socket-mem`` parameter is passed to it when run. 207 208If more memory is requested by explicitly passing a ``-m`` or ``--socket-mem`` value, the application fails. 209However, 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. 210The reason is as follows. 211Suppose the system has 1024 reserved 2 MB pages in socket 0 and 1024 in socket 1. 212If the user requests 128 MB of memory, the 64 pages may not match the constraints: 213 214* The hugepage memory by be given to the application by the kernel in socket 1 only. 215 In this case, if the application attempts to create an object, such as a ring or memory pool in socket 0, it fails. 216 To avoid this issue, it is recommended that the ``--socket-mem`` option be used instead of the ``-m`` option. 217 218* These pages can be located anywhere in physical memory, and, although the DPDK EAL will attempt to allocate memory in contiguous blocks, 219 it is possible that the pages will not be contiguous. In this case, the application is not able to allocate big memory pools. 220 221The socket-mem option can be used to request specific amounts of memory for specific sockets. 222This is accomplished by supplying the ``--socket-mem`` flag followed by amounts of memory requested on each socket, 223for example, supply ``--socket-mem=0,512`` to try and reserve 512 MB for socket 1 only. 224Similarly, 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. 225No memory will be reserved on any CPU socket that is not explicitly referenced, for example, socket 3 in this case. 226If the DPDK cannot allocate enough memory on each socket, the EAL initialization fails. 227 228Additional Sample Applications 229------------------------------ 230 231Additional sample applications are included in the ${RTE_SDK}/examples directory. 232These sample applications may be built and run in a manner similar to that described in earlier sections in this manual. 233In addition, see the *DPDK Sample Applications User Guide* for a description of the application, 234specific instructions on compilation and execution and some explanation of the code. 235 236Additional Test Applications 237---------------------------- 238 239In addition, there are two other applications that are built when the libraries are created. 240The source files for these are in the DPDK/app directory and are called test and testpmd. 241Once the libraries are created, they can be found in the build/app directory. 242 243* The test application provides a variety of specific tests for the various functions in the DPDK. 244 245* The testpmd application provides a number of different packet throughput tests and 246 examples of features such as how to use the Flow Director found in the Intel® 82599 10 Gigabit Ethernet Controller. 247