ceph/src/seastar/dpdk/doc/guides/linux_gsg/build_sample_apps.rst

   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
  31 Compiling and Running Sample Applications
  32 =========================================
  33
  34 The chapter describes how to compile and run applications in an DPDK environment.
  35 It 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
  42 Compiling a Sample Application
  43 ------------------------------
  44
  45 Once an DPDK target environment directory has been created (such as ``x86_64-native-linuxapp-gcc``),
  46 it contains all libraries and header files required to build an application.
  47
  48 When 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
  54 The following is an example of creating the ``helloworld`` application, which runs in the DPDK Linux environment.
  55 This example may be found in the ``${RTE_SDK}/examples`` directory.
  56
  57 The directory contains the ``main.c`` file. This file, when combined with the libraries in the DPDK target environment,
  58 calls the various functions to initialize the DPDK environment,
  59 then launches an entry point (dispatch application) for each core to be utilized.
  60 By default, the binary is generated in the build directory.
  61
  62 .. code-block:: console
  63
  64     cd examples/helloworld/
  65     export RTE_SDK=$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
  96 Running 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
 108 The application is linked with the DPDK target environment's Environmental Abstraction Layer (EAL) library,
 109 which provides some options that are generic to every DPDK application.
 110
 111 The following is the list of options that can be given to the EAL:
 112
 113 .. code-block:: console
 114
 115     ./rte-app [-c COREMASK | -l CORELIST] [-n NUM] [-b <domain:bus:devid.func>] \
 116               [--socket-mem=MB,...] [-d LIB.so|DIR] [-m MB] [-r NUM] [-v] [--file-prefix] \
 117               [--proc-type <primary|secondary|auto>] [-- xen-dom0]
 118
 119 The EAL options are as follows:
 120
 121 * ``-c COREMASK`` or ``-l CORELIST``:
 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. The corelist is
 124   a set of core numbers instead of a bitmap core mask.
 125
 126 * ``-n NUM``:
 127   Number of memory channels per processor socket.
 128
 129 * ``-b <domain:bus:devid.func>``:
 130   Blacklisting of ports; prevent EAL from using specified PCI device
 131   (multiple ``-b`` options are allowed).
 132
 133 * ``--use-device``:
 134   use the specified Ethernet device(s) only. Use comma-separate
 135   ``[domain:]bus:devid.func`` values. Cannot be used with ``-b`` option.
 136
 137 * ``--socket-mem``:
 138   Memory to allocate from hugepages on specific sockets.
 139
 140 * ``-d``:
 141   Add a driver or driver directory to be loaded.
 142   The application should use this option to load the pmd drivers
 143   that are built as shared libraries.
 144
 145 * ``-m MB``:
 146   Memory to allocate from hugepages, regardless of processor socket. It is
 147   recommended that ``--socket-mem`` be used instead of this option.
 148
 149 * ``-r NUM``:
 150   Number of memory ranks.
 151
 152 * ``-v``:
 153   Display version information on startup.
 154
 155 * ``--huge-dir``:
 156   The directory where hugetlbfs is mounted.
 157
 158 * ``--file-prefix``:
 159   The prefix text used for hugepage filenames.
 160
 161 * ``--proc-type``:
 162   The type of process instance.
 163
 164 * ``--xen-dom0``:
 165   Support application running on Xen Domain0 without hugetlbfs.
 166
 167 * ``--vmware-tsc-map``:
 168   Use VMware TSC map instead of native RDTSC.
 169
 170 * ``--base-virtaddr``:
 171   Specify base virtual address.
 172
 173 * ``--vfio-intr``:
 174   Specify interrupt type to be used by VFIO (has no effect if VFIO is not used).
 175
 176 The ``-c`` or ``-l`` and option is mandatory; the others are optional.
 177
 178 Copy the DPDK application binary to your target, then run the application as follows
 179 (assuming the platform has four memory channels per processor socket,
 180 and that cores 0-3 are present and are to be used for running the application)::
 181
 182     ./helloworld -l 0-3 -n 4
 183
 184 .. note::
 185
 186     The ``--proc-type`` and ``--file-prefix`` EAL options are used for running
 187     multiple DPDK processes. See the "Multi-process Sample Application"
 188     chapter in the *DPDK Sample Applications User Guide* and the *DPDK
 189     Programmers Guide* for more details.
 190
 191 Logical Core Use by Applications
 192 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 193
 194 The coremask (-c 0x0f) or corelist (-l 0-3) parameter is always mandatory for DPDK applications.
 195 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.
 196 Since these logical core numbers, and their mapping to specific cores on specific NUMA sockets, can vary from platform to platform,
 197 it is recommended that the core layout for each platform be considered when choosing the coremask/corelist to use in each case.
 198
 199 On initialization of the EAL layer by an DPDK application, the logical cores to be used and their socket location are displayed.
 200 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``.
 201 The physical id attribute listed for each processor indicates the CPU socket to which it belongs.
 202 This can be useful when using other processors to understand the mapping of the logical cores to the sockets.
 203
 204 .. note::
 205
 206     A more graphical view of the logical core layout may be obtained using the ``lstopo`` Linux utility.
 207     On Fedora Linux, this may be installed and run using the following command::
 208
 209         sudo yum install hwloc
 210         ./lstopo
 211
 212 .. warning::
 213
 214     The logical core layout can change between different board layouts and should be checked before selecting an application coremask/corelist.
 215
 216 Hugepage Memory Use by Applications
 217 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 218
 219 When running an application, it is recommended to use the same amount of memory as that allocated for hugepages.
 220 This is done automatically by the DPDK application at startup,
 221 if no ``-m`` or ``--socket-mem`` parameter is passed to it when run.
 222
 223 If more memory is requested by explicitly passing a ``-m`` or ``--socket-mem`` value, the application fails.
 224 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.
 225 The reason is as follows.
 226 Suppose the system has 1024 reserved 2 MB pages in socket 0 and 1024 in socket 1.
 227 If the user requests 128 MB of memory, the 64 pages may not match the constraints:
 228
 229 *   The hugepage memory by be given to the application by the kernel in socket 1 only.
 230     In this case, if the application attempts to create an object, such as a ring or memory pool in socket 0, it fails.
 231     To avoid this issue, it is recommended that the ``--socket-mem`` option be used instead of the ``-m`` option.
 232
 233 *   These pages can be located anywhere in physical memory, and, although the DPDK EAL will attempt to allocate memory in contiguous blocks,
 234     it is possible that the pages will not be contiguous. In this case, the application is not able to allocate big memory pools.
 235
 236 The socket-mem option can be used to request specific amounts of memory for specific sockets.
 237 This is accomplished by supplying the ``--socket-mem`` flag followed by amounts of memory requested on each socket,
 238 for example, supply ``--socket-mem=0,512`` to try and reserve 512 MB for socket 1 only.
 239 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.
 240 No memory will be reserved on any CPU socket that is not explicitly referenced, for example, socket 3 in this case.
 241 If the DPDK cannot allocate enough memory on each socket, the EAL initialization fails.
 242
 243 Additional Sample Applications
 244 ------------------------------
 245
 246 Additional sample applications are included in the ${RTE_SDK}/examples directory.
 247 These sample applications may be built and run in a manner similar to that described in earlier sections in this manual.
 248 In addition, see the *DPDK Sample Applications User Guide* for a description of the application,
 249 specific instructions on compilation and execution and some explanation of the code.
 250
 251 Additional Test Applications
 252 ----------------------------
 253
 254 In addition, there are two other applications that are built when the libraries are created.
 255 The source files for these are in the DPDK/app directory and are called test and testpmd.
 256 Once the libraries are created, they can be found in the build/app directory.
 257
 258 *   The test application provides a variety of specific tests for the various functions in the DPDK.
 259
 260 *   The testpmd application provides a number of different packet throughput tests and
 261     examples of features such as how to use the Flow Director found in the Intel® 82599 10 Gigabit Ethernet Controller.