From patchwork Thu Dec 21 17:27:50 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Liang, Ma" X-Patchwork-Id: 32583 Return-Path: X-Original-To: patchwork@dpdk.org Delivered-To: patchwork@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 862F81B2FD; Thu, 21 Dec 2017 18:28:11 +0100 (CET) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id 236F31B2F3 for ; Thu, 21 Dec 2017 18:28:07 +0100 (CET) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Dec 2017 09:28:07 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.45,436,1508828400"; d="scan'208";a="3800162" Received: from silpixa00398162.ir.intel.com (HELO silpixa00398162.ger.corp.intel.com) ([10.237.223.171]) by fmsmga002.fm.intel.com with ESMTP; 21 Dec 2017 09:28:06 -0800 From: Liang Ma To: jerin.jacob@caviumnetworks.com Cc: dev@dpdk.org, harry.van.haaren@intel.com, bruce.richardson@intel.com, deepak.k.jain@intel.com, john.geary@intel.com, peter.mccarthy@intel.com, seanbh@gmail.com Date: Thu, 21 Dec 2017 17:27:50 +0000 Message-Id: <1513877270-194773-9-git-send-email-liang.j.ma@intel.com> X-Mailer: git-send-email 2.7.5 In-Reply-To: <1513877270-194773-1-git-send-email-liang.j.ma@intel.com> References: <1513877270-194773-1-git-send-email-liang.j.ma@intel.com> Subject: [dpdk-dev] [PATCH v3 8/8] doc: add eventdev opdl pmd docuement X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Add the description about opdl pmd Signed-off-by: Liang Ma Signed-off-by: Peter Mccarthy --- doc/guides/eventdevs/index.rst | 1 + doc/guides/eventdevs/opdl.rst | 162 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 163 insertions(+) create mode 100644 doc/guides/eventdevs/opdl.rst diff --git a/doc/guides/eventdevs/index.rst b/doc/guides/eventdevs/index.rst index ba2048c..07a41bc 100644 --- a/doc/guides/eventdevs/index.rst +++ b/doc/guides/eventdevs/index.rst @@ -40,3 +40,4 @@ application trough the eventdev API. dpaa2 sw octeontx + opdl diff --git a/doc/guides/eventdevs/opdl.rst b/doc/guides/eventdevs/opdl.rst new file mode 100644 index 0000000..4922eaa --- /dev/null +++ b/doc/guides/eventdevs/opdl.rst @@ -0,0 +1,162 @@ +.. BSD LICENSE + Copyright(c) 2017 Intel Corporation. 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. + +OPDL Eventdev Poll Mode Driver +================================== + +The OPDL (Ordered Packet Distribution Library) eventdev is a specific\ +implementation of the eventdev API. It is particularly suited to packet\ +processing workloads that have high throughput and low latency requirements.\ +All packets follow the same path through the device. The order in which\ +packets follow is determinted by the order in which queues are set up.\ +Events are left on the ring until they are transmitted. As a result packets\ +do not go out of order + + +Features +-------- + +The OPDL eventdev implements a subset of features of the eventdev API; + +Queues + * Atomic + * Ordered (Parallel is supported as parallel is a subset of Ordered) + * Single-Link + +Ports + * Load balanced (for Atomic, Ordered, Parallel queues) + * Single Link (for single-link queues) + + +Configuration and Options +------------------------- + +The software eventdev is a vdev device, and as such can be created from the +application code, or from the EAL command line: + +* Call ``rte_vdev_init("event_opdl0")`` from the application + +* Use ``--vdev="event_opdl0"`` in the EAL options, which will call + rte_vdev_init() internally + +Example: + +.. code-block:: console + + ./your_eventdev_application --vdev="event_opdl0" + + +Single Port Queue +~~~~~~~~~~~~~~~~~ + +It is possible to create a Single Port Queue ``RTE_EVENT_QUEUE_CFG_SINGLE_LINK``. +Packets dequeued from this queue do not need to be re-enqueued (as is the +case with an ordered queue). The purpose of this queue is to allow for +asynchronous handling of packets in the middle of a pipeline. Ordered +queues in the middle of a pipeline cannot delete packets. + + +Queue Dependencies +~~~~~~~~~~~~~~~~~~ + +As stated the order in which packets travel through queues is static in +nature. They go through the queues in the order the queues are setup at +initialisation ``rte_event_queue_setup()``. For example if an application +sets up 3 queues, Q0, Q1, Q2 and has 3 assoicated ports P0, P1, P2 and +P3 then packets must be + + * Enqueued onto Q0 (typically through P0), then + + * Dequeued from Q0 (typically through P1), then + + * Enqueued onto Q1 (also through P1), then + + * Dequeued from Q2 (typically through P2), then + + * Enqueued onto Q3 (also through P2), then + + * Dequeued from Q3 (typically through P3) and then transmitted on the relevant \ + eth port + + +Limitations +----------- + +The opdl implementation has a number of limitations. These limitations are +due to the static nature of the underlying queues. It is because of this +that the implementation can achieve such high throughput and low latency + +The following list is a comprehensive outline of the what is supported and +the limitations / restrictions imposed by the opdl pmd + + - The order in which packets moved between queues is static and fixed \ + (dynamic scheduling is not supported). + + - NEW, RELEASE are not explicitly supported. RX (first enqueue) implicitly \ + adds NEW event types, and TX (last dequeue) implicitly does RELEASE event types. + + - All packets follow the same path through device queues. + + - Flows within queues are NOT supported. + + - Event priority is NOT supported. + + - Once the device is stopped all inflight events are lost. Applications should \ + clear all inflight events before stopping it. + + - Each port can only be associated with one queue. + + - Each queue can have multiple ports associated with it. + + - Each worker core has to dequeue the maximum burst size for that port. + + - For performance, the rte_event flow_id should not be updated once packet\ + is enqueued on RX. + + + +Validation & Statistics +~~~~~~~~~~~~~~~~~~~~~~~ + +Validation can be turned on through a command line parameter + +.. code-block:: console + + --vdev="event_opdl0,do_validation=1,self_test=1" + +If validation is turned on every packet (as opposed to just the first in +each burst), is validated to have come from the right queue. Statistics +are also produced in this mode. The statistics are available through the +eventdev xstats API. Statistics are per port as follows: + + - claim_pkts_requested + - claim_pkts_granted + - claim_non_empty + - claim_empty + - total_cycles