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 31Distributor Sample Application 32============================== 33 34The distributor sample application is a simple example of packet distribution 35to cores using the Data Plane Development Kit (DPDK). 36 37Overview 38-------- 39 40The distributor application performs the distribution of packets that are received 41on an RX_PORT to different cores. When processed by the cores, the destination 42port of a packet is the port from the enabled port mask adjacent to the one on 43which the packet was received, that is, if the first four ports are enabled 44(port mask 0xf), ports 0 and 1 RX/TX into each other, and ports 2 and 3 RX/TX 45into each other. 46 47This application can be used to benchmark performance using the traffic 48generator as shown in the figure below. 49 50.. _figure_dist_perf: 51 52.. figure:: img/dist_perf.* 53 54 Performance Benchmarking Setup (Basic Environment) 55 56 57Compiling the Application 58------------------------- 59 60#. Go to the sample application directory: 61 62 .. code-block:: console 63 64 export RTE_SDK=/path/to/rte_sdk 65 cd ${RTE_SDK}/examples/distributor 66 67#. Set the target (a default target is used if not specified). For example: 68 69 .. code-block:: console 70 71 export RTE_TARGET=x86_64-native-linuxapp-gcc 72 73 See the DPDK Getting Started Guide for possible RTE_TARGET values. 74 75#. Build the application: 76 77 .. code-block:: console 78 79 make 80 81Running the Application 82----------------------- 83 84#. The application has a number of command line options: 85 86 .. code-block:: console 87 88 ./build/distributor_app [EAL options] -- -p PORTMASK 89 90 where, 91 92 * -p PORTMASK: Hexadecimal bitmask of ports to configure 93 94#. To run the application in linuxapp environment with 10 lcores, 4 ports, 95 issue the command: 96 97 .. code-block:: console 98 99 $ ./build/distributor_app -l 1-9,22 -n 4 -- -p f 100 101#. Refer to the DPDK Getting Started Guide for general information on running 102 applications and the Environment Abstraction Layer (EAL) options. 103 104Explanation 105----------- 106 107The distributor application consists of four types of threads: a receive 108thread (``lcore_rx()``), a distributor thread (``lcore_dist()``), a set of 109worker threads (``lcore_worker()``), and a transmit thread(``lcore_tx()``). 110How these threads work together is shown in :numref:`figure_dist_app` below. 111The ``main()`` function launches threads of these four types. Each thread 112has a while loop which will be doing processing and which is terminated 113only upon SIGINT or ctrl+C. 114 115The receive thread receives the packets using ``rte_eth_rx_burst()`` and will 116enqueue them to an rte_ring. The distributor thread will dequeue the packets 117from the ring and assign them to workers (using ``rte_distributor_process()`` API). 118This assignment is based on the tag (or flow ID) of the packet - indicated by 119the hash field in the mbuf. For IP traffic, this field is automatically filled 120by the NIC with the "usr" hash value for the packet, which works as a per-flow 121tag. The distributor thread communicates with the worker threads using a 122cache-line swapping mechanism, passing up to 8 mbuf pointers at a time 123(one cache line) to each worker. 124 125More than one worker thread can exist as part of the application, and these 126worker threads do simple packet processing by requesting packets from 127the distributor, doing a simple XOR operation on the input port mbuf field 128(to indicate the output port which will be used later for packet transmission) 129and then finally returning the packets back to the distributor thread. 130 131The distributor thread will then call the distributor api 132``rte_distributor_returned_pkts()`` to get the processed packets, and will enqueue 133them to another rte_ring for transfer to the TX thread for transmission on the 134output port. The transmit thread will dequeue the packets from the ring and 135transmit them on the output port specified in packet mbuf. 136 137Users who wish to terminate the running of the application have to press ctrl+C 138(or send SIGINT to the app). Upon this signal, a signal handler provided 139in the application will terminate all running threads gracefully and print 140final statistics to the user. 141 142.. _figure_dist_app: 143 144.. figure:: img/dist_app.* 145 146 Distributor Sample Application Layout 147 148 149Debug Logging Support 150--------------------- 151 152Debug logging is provided as part of the application; the user needs to uncomment 153the line "#define DEBUG" defined in start of the application in main.c to enable debug logs. 154 155Statistics 156---------- 157 158The main function will print statistics on the console every second. These 159statistics include the number of packets enqueued and dequeued at each stage 160in the application, and also key statistics per worker, including how many 161packets of each burst size (1-8) were sent to each worker thread. 162 163Application Initialization 164-------------------------- 165 166Command line parsing is done in the same way as it is done in the L2 Forwarding Sample 167Application. See :ref:`l2_fwd_app_cmd_arguments`. 168 169Mbuf pool initialization is done in the same way as it is done in the L2 Forwarding 170Sample Application. See :ref:`l2_fwd_app_mbuf_init`. 171 172Driver Initialization is done in same way as it is done in the L2 Forwarding Sample 173Application. See :ref:`l2_fwd_app_dvr_init`. 174 175RX queue initialization is done in the same way as it is done in the L2 Forwarding 176Sample Application. See :ref:`l2_fwd_app_rx_init`. 177 178TX queue initialization is done in the same way as it is done in the L2 Forwarding 179Sample Application. See :ref:`l2_fwd_app_tx_init`. 180