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diff --git a/doc/guides/sample_app_ug/dist_app.rst b/doc/guides/sample_app_ug/dist_app.rst new file mode 100644 index 00000000..e242748f --- /dev/null +++ b/doc/guides/sample_app_ug/dist_app.rst @@ -0,0 +1,175 @@ +.. BSD LICENSE + Copyright(c) 2010-2014 Intel Corporation. All rights reserved. + All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in + the documentation and/or other materials provided with the + distribution. + * Neither the name of Intel Corporation nor the names of its + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +Distributor Sample Application +============================== + +The distributor sample application is a simple example of packet distribution +to cores using the Data Plane Development Kit (DPDK). + +Overview +-------- + +The distributor application performs the distribution of packets that are received +on an RX_PORT to different cores. When processed by the cores, the destination +port of a packet is the port from the enabled port mask adjacent to the one on +which the packet was received, that is, if the first four ports are enabled +(port mask 0xf), ports 0 and 1 RX/TX into each other, and ports 2 and 3 RX/TX +into each other. + +This application can be used to benchmark performance using the traffic +generator as shown in the figure below. + +.. _figure_dist_perf: + +.. figure:: img/dist_perf.* + + Performance Benchmarking Setup (Basic Environment) + + +Compiling the Application +------------------------- + +#. Go to the sample application directory: + + .. code-block:: console + + export RTE_SDK=/path/to/rte_sdk + cd ${RTE_SDK}/examples/distributor + +#. Set the target (a default target is used if not specified). For example: + + .. code-block:: console + + export RTE_TARGET=x86_64-native-linuxapp-gcc + + See the DPDK Getting Started Guide for possible RTE_TARGET values. + +#. Build the application: + + .. code-block:: console + + make + +Running the Application +----------------------- + +#. The application has a number of command line options: + + .. code-block:: console + + ./build/distributor_app [EAL options] -- -p PORTMASK + + where, + + * -p PORTMASK: Hexadecimal bitmask of ports to configure + +#. To run the application in linuxapp environment with 10 lcores, 4 ports, + issue the command: + + .. code-block:: console + + $ ./build/distributor_app -c 0x4003fe -n 4 -- -p f + +#. Refer to the DPDK Getting Started Guide for general information on running + applications and the Environment Abstraction Layer (EAL) options. + +Explanation +----------- + +The distributor application consists of three types of threads: a receive +thread (lcore_rx()), a set of worker threads(lcore_worker()) +and a transmit thread(lcore_tx()). How these threads work together is shown +in :numref:`figure_dist_app` below. The main() function launches threads of these three types. +Each thread has a while loop which will be doing processing and which is +terminated only upon SIGINT or ctrl+C. The receive and transmit threads +communicate using a software ring (rte_ring structure). + +The receive thread receives the packets using rte_eth_rx_burst() and gives +them to the distributor (using rte_distributor_process() API) which will +be called in context of the receive thread itself. The distributor distributes +the packets to workers threads based on the tagging of the packet - +indicated by the hash field in the mbuf. For IP traffic, this field is +automatically filled by the NIC with the "usr" hash value for the packet, +which works as a per-flow tag. + +More than one worker thread can exist as part of the application, and these +worker threads do simple packet processing by requesting packets from +the distributor, doing a simple XOR operation on the input port mbuf field +(to indicate the output port which will be used later for packet transmission) +and then finally returning the packets back to the distributor in the RX thread. + +Meanwhile, the receive thread will call the distributor api +rte_distributor_returned_pkts() to get the packets processed, and will enqueue +them to a ring for transfer to the TX thread for transmission on the output port. +The transmit thread will dequeue the packets from the ring and transmit them on +the output port specified in packet mbuf. + +Users who wish to terminate the running of the application have to press ctrl+C +(or send SIGINT to the app). Upon this signal, a signal handler provided +in the application will terminate all running threads gracefully and print +final statistics to the user. + +.. _figure_dist_app: + +.. figure:: img/dist_app.* + + Distributor Sample Application Layout + + +Debug Logging Support +--------------------- + +Debug logging is provided as part of the application; the user needs to uncomment +the line "#define DEBUG" defined in start of the application in main.c to enable debug logs. + +Statistics +---------- + +Upon SIGINT (or) ctrl+C, the print_stats() function displays the count of packets +processed at the different stages in the application. + +Application Initialization +-------------------------- + +Command line parsing is done in the same way as it is done in the L2 Forwarding Sample +Application. See :ref:`l2_fwd_app_cmd_arguments`. + +Mbuf pool initialization is done in the same way as it is done in the L2 Forwarding +Sample Application. See :ref:`l2_fwd_app_mbuf_init`. + +Driver Initialization is done in same way as it is done in the L2 Forwarding Sample +Application. See :ref:`l2_fwd_app_dvr_init`. + +RX queue initialization is done in the same way as it is done in the L2 Forwarding +Sample Application. See :ref:`l2_fwd_app_rx_init`. + +TX queue initialization is done in the same way as it is done in the L2 Forwarding +Sample Application. See :ref:`l2_fwd_app_tx_init`. |