--- /dev/null
+.. BSD LICENSE
+ Copyright(c) 2016 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.
+
+
+L2 Forwarding Sample Application with Cache Allocation Technology (CAT)
+=======================================================================
+
+Basic Forwarding sample application is a simple *skeleton* example of
+a forwarding application. It has been extended to make use of CAT via extended
+command line options and linking against the libpqos library.
+
+It is intended as a demonstration of the basic components of a DPDK forwarding
+application and use of the libpqos library to program CAT.
+For more detailed implementations see the L2 and L3 forwarding
+sample applications.
+
+CAT and Code Data Prioritization (CDP) features allow management of the CPU's
+last level cache. CAT introduces classes of service (COS) that are essentially
+bitmasks. In current CAT implementations, a bit in a COS bitmask corresponds to
+one cache way in last level cache.
+A CPU core is always assigned to one of the CAT classes.
+By programming CPU core assignment and COS bitmasks, applications can be given
+exclusive, shared, or mixed access to the CPU's last level cache.
+CDP extends CAT so that there are two bitmasks per COS,
+one for data and one for code.
+The number of classes and number of valid bits in a COS bitmask is CPU model
+specific and COS bitmasks need to be contiguous. Sample code calls this bitmask
+``cbm`` or capacity bitmask.
+By default, after reset, all CPU cores are assigned to COS 0 and all classes
+are programmed to allow fill into all cache ways.
+CDP is off by default.
+
+For more information about CAT please see:
+
+* https://github.com/01org/intel-cmt-cat
+
+White paper demonstrating example use case:
+
+* `Increasing Platform Determinism with Platform Quality of Service for the Data Plane Development Kit <http://www.intel.com/content/www/us/en/communications/increasing-platform-determinism-pqos-dpdk-white-paper.html>`_
+
+Compiling the Application
+-------------------------
+
+Requires ``libpqos`` from Intel's
+`intel-cmt-cat software package <https://github.com/01org/intel-cmt-cat>`_
+hosted on GitHub repository. For installation notes, please see ``README`` file.
+
+GIT:
+
+* https://github.com/01org/intel-cmt-cat
+
+To compile the application export the path to PQoS lib
+and the DPDK source tree and go to the example directory:
+
+.. code-block:: console
+
+ export PQOS_INSTALL_PATH=/path/to/libpqos
+ export RTE_SDK=/path/to/rte_sdk
+
+ cd ${RTE_SDK}/examples/l2fwd-cat
+
+Set the target, 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 as follows:
+
+.. code-block:: console
+
+ make
+
+
+Running the Application
+-----------------------
+
+To run the example in a ``linuxapp`` environment and enable CAT on cpus 0-2:
+
+.. code-block:: console
+
+ ./build/l2fwd-cat -c 2 -n 4 -- --l3ca="0x3@(0-2)"
+
+or to enable CAT and CDP on cpus 1,3:
+
+.. code-block:: console
+
+ ./build/l2fwd-cat -c 2 -n 4 -- --l3ca="(0x00C00,0x00300)@(1,3)"
+
+If CDP is not supported it will fail with following error message:
+
+.. code-block:: console
+
+ PQOS: CDP requested but not supported.
+ PQOS: Requested CAT configuration is not valid!
+ PQOS: Shutting down PQoS library...
+ EAL: Error - exiting with code: 1
+ Cause: PQOS: L3CA init failed!
+
+The option to enable CAT is:
+
+* ``--l3ca='<common_cbm@cpus>[,<(code_cbm,data_cbm)@cpus>...]'``:
+
+ where ``cbm`` stands for capacity bitmask and must be expressed in
+ hexadecimal form.
+
+ ``common_cbm`` is a single mask, for a CDP enabled system, a group of two
+ masks (``code_cbm`` and ``data_cbm``) is used.
+
+ ``(`` and ``)`` are necessary if it's a group.
+
+ ``cpus`` could be a single digit/range or a group and must be expressed in
+ decimal form.
+
+ ``(`` and ``)`` are necessary if it's a group.
+
+ e.g. ``--l3ca='0x00F00@(1,3),0x0FF00@(4-6),0xF0000@7'``
+
+ * cpus 1 and 3 share its 4 ways with cpus 4, 5 and 6;
+
+ * cpus 4, 5 and 6 share half (4 out of 8 ways) of its L3 with cpus 1 and 3;
+
+ * cpus 4, 5 and 6 have exclusive access to 4 out of 8 ways;
+
+ * cpu 7 has exclusive access to all of its 4 ways;
+
+ e.g. ``--l3ca='(0x00C00,0x00300)@(1,3)'`` for CDP enabled system
+
+ * cpus 1 and 3 have access to 2 ways for code and 2 ways for data, code and
+ data ways are not overlapping.
+
+
+Refer to *DPDK Getting Started Guide* for general information on running
+applications and the Environment Abstraction Layer (EAL) options.
+
+
+To reset or list CAT configuration and control CDP please use ``pqos`` tool
+from Intel's
+`intel-cmt-cat software package <https://github.com/01org/intel-cmt-cat>`_.
+
+To enabled or disable CDP:
+
+.. code-block:: console
+
+ sudo ./pqos -S cdp-on
+
+ sudo ./pqos -S cdp-off
+
+to reset CAT configuration:
+
+.. code-block:: console
+
+ sudo ./pqos -R
+
+to list CAT config:
+
+.. code-block:: console
+
+ sudo ./pqos -s
+
+For more info about ``pqos`` tool please see its man page or
+`intel-cmt-cat wiki <https://github.com/01org/intel-cmt-cat/wiki>`_.
+
+
+Explanation
+-----------
+
+The following sections provide an explanation of the main components of the
+code.
+
+All DPDK library functions used in the sample code are prefixed with ``rte_``
+and are explained in detail in the *DPDK API Documentation*.
+
+
+The Main Function
+~~~~~~~~~~~~~~~~~
+
+The ``main()`` function performs the initialization and calls the execution
+threads for each lcore.
+
+The first task is to initialize the Environment Abstraction Layer (EAL). The
+``argc`` and ``argv`` arguments are provided to the ``rte_eal_init()``
+function. The value returned is the number of parsed arguments:
+
+.. code-block:: c
+
+ int ret = rte_eal_init(argc, argv);
+ if (ret < 0)
+ rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");
+
+The next task is to initialize the PQoS library and configure CAT. The
+``argc`` and ``argv`` arguments are provided to the ``cat_init()``
+function. The value returned is the number of parsed arguments:
+
+.. code-block:: c
+
+ int ret = cat_init(argc, argv);
+ if (ret < 0)
+ rte_exit(EXIT_FAILURE, "PQOS: L3CA init failed!\n");
+
+``cat_init()`` is a wrapper function which parses the command, validates
+the requested parameters and configures CAT accordingly.
+
+Parsing of command line arguments is done in ``parse_args(...)``.
+libpqos is then initialized with the ``pqos_init(...)`` call. Next, libpqos is
+queried for system CPU information and L3CA capabilities via
+``pqos_cap_get(...)`` and ``pqos_cap_get_type(..., PQOS_CAP_TYPE_L3CA, ...)``
+calls. When all capability and topology information is collected, the requested
+CAT configuration is validated. A check is then performed (on per socket basis)
+for a sufficient number of un-associated COS. COS are selected and
+configured via the ``pqos_l3ca_set(...)`` call. Finally, COS are associated to
+relevant CPUs via ``pqos_l3ca_assoc_set(...)`` calls.
+
+``atexit(...)`` is used to register ``cat_exit(...)`` to be called on
+a clean exit. ``cat_exit(...)`` performs a simple CAT clean-up, by associating
+COS 0 to all involved CPUs via ``pqos_l3ca_assoc_set(...)`` calls.
\ No newline at end of file
Code Review / deb_dpdk.git / blobdiff