From 97f17497d162afdb82c8704bf097f0fee3724b2e Mon Sep 17 00:00:00 2001 From: "C.J. Collier" Date: Tue, 14 Jun 2016 07:50:17 -0700 Subject: Imported Upstream version 16.04 Change-Id: I77eadcd8538a9122e4773cbe55b24033dc451757 Signed-off-by: C.J. Collier --- doc/guides/sample_app_ug/keep_alive.rst | 190 ++++++++++++++++++++++++++++++++ 1 file changed, 190 insertions(+) create mode 100644 doc/guides/sample_app_ug/keep_alive.rst (limited to 'doc/guides/sample_app_ug/keep_alive.rst') diff --git a/doc/guides/sample_app_ug/keep_alive.rst b/doc/guides/sample_app_ug/keep_alive.rst new file mode 100644 index 00000000..38973779 --- /dev/null +++ b/doc/guides/sample_app_ug/keep_alive.rst @@ -0,0 +1,190 @@ + +.. BSD LICENSE + Copyright(c) 2015-2016 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. + +Keep Alive Sample Application +============================= + +The Keep Alive application is a simple example of a +heartbeat/watchdog for packet processing cores. It demonstrates how +to detect 'failed' DPDK cores and notify a fault management entity +of this failure. Its purpose is to ensure the failure of the core +does not result in a fault that is not detectable by a management +entity. + + +Overview +-------- + +The application demonstrates how to protect against 'silent outages' +on packet processing cores. A Keep Alive Monitor Agent Core (master) +monitors the state of packet processing cores (worker cores) by +dispatching pings at a regular time interval (default is 5ms) and +monitoring the state of the cores. Cores states are: Alive, MIA, Dead +or Buried. MIA indicates a missed ping, and Dead indicates two missed +pings within the specified time interval. When a core is Dead, a +callback function is invoked to restart the packet processing core; +A real life application might use this callback function to notify a +higher level fault management entity of the core failure in order to +take the appropriate corrective action. + +Note: Only the worker cores are monitored. A local (on the host) mechanism +or agent to supervise the Keep Alive Monitor Agent Core DPDK core is required +to detect its failure. + +Note: This application is based on the :doc:`l2_forward_real_virtual`. As +such, the initialization and run-time paths are very similar to those +of the L2 forwarding application. + +Compiling the Application +------------------------- + +To compile the application: + +#. Go to the sample application directory: + + .. code-block:: console + + export RTE_SDK=/path/to/rte_sdk cd ${RTE_SDK}/examples/keep_alive + +#. 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/l2fwd-keepalive [EAL options] \ + -- -p PORTMASK [-q NQ] [-K PERIOD] [-T PERIOD] + +where, + +* ``p PORTMASK``: A hexadecimal bitmask of the ports to configure + +* ``q NQ``: A number of queues (=ports) per lcore (default is 1) + +* ``K PERIOD``: Heartbeat check period in ms(5ms default; 86400 max) + +* ``T PERIOD``: statistics will be refreshed each PERIOD seconds (0 to + disable, 10 default, 86400 maximum). + +To run the application in linuxapp environment with 4 lcores, 16 ports +8 RX queues per lcore and a ping interval of 10ms, issue the command: + +.. code-block:: console + + ./build/l2fwd-keepalive -c f -n 4 -- -q 8 -p ffff -K 10 + +Refer to the *DPDK Getting Started Guide* for general information on +running applications and the Environment Abstraction Layer (EAL) +options. + + +Explanation +----------- + +The following sections provide some explanation of the The +Keep-Alive/'Liveliness' conceptual scheme. As mentioned in the +overview section, the initialization and run-time paths are very +similar to those of the :doc:`l2_forward_real_virtual`. + +The Keep-Alive/'Liveliness' conceptual scheme: + +* A Keep- Alive Agent Runs every N Milliseconds. + +* DPDK Cores respond to the keep-alive agent. + +* If keep-alive agent detects time-outs, it notifies the + fault management entity through a callback function. + +The following sections provide some explanation of the code aspects +that are specific to the Keep Alive sample application. + +The keepalive functionality is initialized with a struct +rte_keepalive and the callback function to invoke in the +case of a timeout. + +.. code-block:: c + + rte_global_keepalive_info = rte_keepalive_create(&dead_core, NULL); + if (rte_global_keepalive_info == NULL) + rte_exit(EXIT_FAILURE, "keepalive_create() failed"); + +The function that issues the pings keepalive_dispatch_pings() +is configured to run every check_period milliseconds. + +.. code-block:: c + + if (rte_timer_reset(&hb_timer, + (check_period * rte_get_timer_hz()) / 1000, + PERIODICAL, + rte_lcore_id(), + &rte_keepalive_dispatch_pings, + rte_global_keepalive_info + ) != 0 ) + rte_exit(EXIT_FAILURE, "Keepalive setup failure.\n"); + +The rest of the initialization and run-time path follows +the same paths as the the L2 forwarding application. The only +addition to the main processing loop is the mark alive +functionality and the example random failures. + +.. code-block:: c + + rte_keepalive_mark_alive(&rte_global_keepalive_info); + cur_tsc = rte_rdtsc(); + + /* Die randomly within 7 secs for demo purposes.. */ + if (cur_tsc - tsc_initial > tsc_lifetime) + break; + +The rte_keepalive_mark_alive function simply sets the core state to alive. + +.. code-block:: c + + static inline void + rte_keepalive_mark_alive(struct rte_keepalive *keepcfg) + { + keepcfg->state_flags[rte_lcore_id()] = ALIVE; + } -- cgit 1.2.3-korg