DPDK patches and discussions
 help / color / mirror / Atom feed
From: Ferruh Yigit <ferruh.yigit@intel.com>
To: dev@dpdk.org, Keith Wiles <keith.wiles@intel.com>
Cc: Ferruh Yigit <ferruh.yigit@intel.com>,
	Stephen Hemminger <stephen@networkplumber.org>,
	Thomas Monjalon <thomas@monjalon.net>
Subject: [dpdk-dev] [PATCH] doc: note KNI alternatives and deprecation plan
Date: Wed, 23 Jun 2021 18:31:42 +0100
Message-ID: <20210623173142.3803801-1-ferruh.yigit@intel.com> (raw)

Add a note that KNI kernel module will be moved to dpdk-kmods git repo
and there is a long term plan to deprecate it.

Also add some more details on the alternatives to KNI and cons of the
KNI against these alternatives.

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
 doc/guides/nics/tap.rst                       |  2 +
 .../prog_guide/kernel_nic_interface.rst       | 38 +++++++++++++++++--
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/doc/guides/nics/tap.rst b/doc/guides/nics/tap.rst
index 3ce696b605d1..07315fe32422 100644
--- a/doc/guides/nics/tap.rst
+++ b/doc/guides/nics/tap.rst
@@ -1,6 +1,8 @@
 ..  SPDX-License-Identifier: BSD-3-Clause
     Copyright(c) 2016 Intel Corporation.
 
+.. _TunTap_PMD:
+
 Tun|Tap Poll Mode Driver
 ========================
 
diff --git a/doc/guides/prog_guide/kernel_nic_interface.rst b/doc/guides/prog_guide/kernel_nic_interface.rst
index 1ce03ec1a374..29f8c92fd9d6 100644
--- a/doc/guides/prog_guide/kernel_nic_interface.rst
+++ b/doc/guides/prog_guide/kernel_nic_interface.rst
@@ -6,16 +6,48 @@
 Kernel NIC Interface
 ====================
 
+.. Note::
+
+   KNI kernel module will be removed from main git repository to `dpdk-kmods <https://git.dpdk.org/dpdk-kmods/>`_
+   repository by the `DPDK technical board decision <https://mails.dpdk.org/archives/dev/2021-January/197077.html>`_.
+   Also there is a `long term plan <https://mails.dpdk.org/archives/dev/2021-May/209026.html>`_ to deprecate the KNI.
+
+   :ref:`virtio_user_as_exceptional_path` alternative is preferred way for
+   interfacing with Linux network stack as it is being in-kernel solution and
+   similar performance expectations.
+
 The DPDK Kernel NIC Interface (KNI) allows userspace applications access to the Linux* control plane.
 
-The benefits of using the DPDK KNI are:
+KNI allows an interface with the kernel network stack and allows management of
+DPDK ports using standard Linux net tools such as ``ethtool``, ``ifconfig`` and
+``tcpdump``.
+
+Main use case of KNI is get/receive exception packets from/to Linux network
+stack while main datapath IO is done bypassing the networking stack.
+
+There are other alternatives to KNI, all are available in the upstream Linux:
+
+#. :ref:`TunTap_PMD` as wrapper to `Linux tun/tap
+   <https://www.kernel.org/doc/Documentation/networking/tuntap.txt>`_
+
+#. :ref:`virtio_user_as_exceptional_path`
+
+The benefits of using the DPDK KNI against alternatives are:
 
 *   Faster than existing Linux TUN/TAP interfaces
     (by eliminating system calls and copy_to_user()/copy_from_user() operations.
 
-*   Allows management of DPDK ports using standard Linux net tools such as ethtool, ifconfig and tcpdump.
+The cons of the DPDK KNI are:
+
+* It is out-of-tree Linux kernel module and it can't be distributed as binary as
+  part of OSV DPDK packages. This makes it harder to consume, although it is
+  always possible to compile it from the source code.
+
+* As it shares memory between userspace and kernelspace, and kernel part
+  directly uses input provided by userspace, it is not safe. This makes hard to
+  upstream the module.
 
-*   Allows an interface with the kernel network stack.
+* Only a subset of control commands are supported by KNI.
 
 The components of an application using the DPDK Kernel NIC Interface are shown in :numref:`figure_kernel_nic_intf`.
 
-- 
2.31.1


             reply	other threads:[~2021-06-23 17:32 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-23 17:31 Ferruh Yigit [this message]
2021-06-23 18:33 ` Stephen Hemminger
2021-06-24  8:19   ` Ferruh Yigit
2021-07-30 12:48 ` Olivier Matz
2021-11-23 10:21   ` Ferruh Yigit
2021-08-20 12:58 ` David Marchand
2021-11-23 10:42   ` Ferruh Yigit
2021-11-23 12:08 ` [PATCH v2 1/2] doc: note KNI alternatives Ferruh Yigit
2021-11-23 12:08   ` [PATCH v2 2/2] doc: announce KNI deprecation Ferruh Yigit
2021-11-24 14:00     ` Thomas Monjalon
2021-11-24 13:58   ` [PATCH v2 1/2] doc: note KNI alternatives Thomas Monjalon
2021-11-24 14:19     ` Ferruh Yigit
2021-11-24 17:16 ` [PATCH v3 " Ferruh Yigit
2021-11-24 17:16   ` [PATCH v3 2/2] doc: announce KNI deprecation Ferruh Yigit
2021-12-01 16:31   ` [PATCH v3 1/2] doc: note KNI alternatives Morten Brørup

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210623173142.3803801-1-ferruh.yigit@intel.com \
    --to=ferruh.yigit@intel.com \
    --cc=dev@dpdk.org \
    --cc=keith.wiles@intel.com \
    --cc=stephen@networkplumber.org \
    --cc=thomas@monjalon.net \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror http://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ http://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git