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_22: 51 52**Figure 22. Performance Benchmarking Setup (Basic Environment)** 53 54|dist_perf| 55 56Compiling the Application 57------------------------- 58 59#. Go to the sample application directory: 60 61 .. code-block:: console 62 63 export RTE_SDK=/path/to/rte_sdk 64 cd ${RTE_SDK}/examples/distributor 65 66#. Set the target (a default target is used if not specified). For example: 67 68 .. code-block:: console 69 70 export RTE_TARGET=x86_64-native-linuxapp-gcc 71 72 See the DPDK Getting Started Guide for possible RTE_TARGET values. 73 74#. Build the application: 75 76 .. code-block:: console 77 78 make 79 80Running the Application 81----------------------- 82 83#. The application has a number of command line options: 84 85 .. code-block:: console 86 87 ./build/distributor_app [EAL options] -- -p PORTMASK 88 89 where, 90 91 * -p PORTMASK: Hexadecimal bitmask of ports to configure 92 93#. To run the application in linuxapp environment with 10 lcores, 4 ports, 94 issue the command: 95 96 .. code-block:: console 97 98 $ ./build/distributor_app -c 0x4003fe -n 4 -- -p f 99 100#. Refer to the DPDK Getting Started Guide for general information on running 101 applications and the Environment Abstraction Layer (EAL) options. 102 103Explanation 104----------- 105 106The distributor application consists of three types of threads: a receive 107thread (lcore_rx()), a set of worker threads(locre_worker()) 108and a transmit thread(lcore_tx()). How these threads work together is shown 109in Fig2 below. The main() function launches threads of these three types. 110Each thread has a while loop which will be doing processing and which is 111terminated only upon SIGINT or ctrl+C. The receive and transmit threads 112communicate using a software ring (rte_ring structure). 113 114The receive thread receives the packets using rte_eth_rx_burst() and gives 115them to the distributor (using rte_distributor_process() API) which will 116be called in context of the receive thread itself. The distributor distributes 117the packets to workers threads based on the tagging of the packet - 118indicated by the hash field in the mbuf. For IP traffic, this field is 119automatically filled by the NIC with the "usr" hash value for the packet, 120which works as a per-flow tag. 121 122More than one worker thread can exist as part of the application, and these 123worker threads do simple packet processing by requesting packets from 124the distributor, doing a simple XOR operation on the input port mbuf field 125(to indicate the output port which will be used later for packet transmission) 126and then finally returning the packets back to the distributor in the RX thread. 127 128Meanwhile, the receive thread will call the distributor api 129rte_distributor_returned_pkts() to get the packets processed, and will enqueue 130them to a ring for transfer to the TX thread for transmission on the output port. 131The transmit thread will dequeue the packets from the ring and transmit them on 132the output port specified in packet mbuf. 133 134Users who wish to terminate the running of the application have to press ctrl+C 135(or send SIGINT to the app). Upon this signal, a signal handler provided 136in the application will terminate all running threads gracefully and print 137final statistics to the user. 138 139.. _figure_23: 140 141**Figure 23. Distributor Sample Application Layout** 142 143|dist_app| 144 145Debug Logging Support 146--------------------- 147 148Debug logging is provided as part of the application; the user needs to uncomment 149the line "#define DEBUG" defined in start of the application in main.c to enable debug logs. 150 151Statistics 152---------- 153 154Upon SIGINT (or) ctrl+C, the print_stats() function displays the count of packets 155processed at the different stages in the application. 156 157Application Initialization 158-------------------------- 159 160Command line parsing is done in the same way as it is done in the L2 Forwarding Sample 161Application. See Section 9.4.1, "Command Line Arguments". 162 163Mbuf pool initialization is done in the same way as it is done in the L2 Forwarding 164Sample Application. See Section 9.4.2, "Mbuf Pool Initialization". 165 166Driver Initialization is done in same way as it is done in the L2 Forwarding Sample 167Application. See Section 9.4.3, "Driver Initialization". 168 169RX queue initialization is done in the same way as it is done in the L2 Forwarding 170Sample Application. See Section 9.4.4, "RX Queue Initialization". 171 172TX queue initialization is done in the same way as it is done in the L2 Forwarding 173Sample Application. See Section 9.4.5, "TX Queue Initialization". 174 175.. |dist_perf| image:: img/dist_perf.svg 176 177.. |dist_app| image:: img/dist_app.svg 178
