From patchwork Tue Feb 16 11:22:38 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Kavanagh X-Patchwork-Id: 583335 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from archives.nicira.com (unknown [IPv6:2600:3c00::f03c:91ff:fe6e:bdf7]) by ozlabs.org (Postfix) with ESMTP id E0FB61401E7 for ; Tue, 16 Feb 2016 22:22:50 +1100 (AEDT) Received: from archives.nicira.com (localhost [127.0.0.1]) by archives.nicira.com (Postfix) with ESMTP id E95E3102F7; Tue, 16 Feb 2016 03:22:48 -0800 (PST) X-Original-To: dev@openvswitch.org Delivered-To: dev@openvswitch.org Received: from mx1e3.cudamail.com (mx1.cudamail.com [69.90.118.67]) by archives.nicira.com (Postfix) with ESMTPS id 4EA80102F6 for ; Tue, 16 Feb 2016 03:22:47 -0800 (PST) Received: from bar5.cudamail.com (localhost [127.0.0.1]) by mx1e3.cudamail.com (Postfix) with ESMTPS id 95A15420559 for ; Tue, 16 Feb 2016 04:22:46 -0700 (MST) X-ASG-Debug-ID: 1455621765-09eadd7d13ec300001-byXFYA Received: from mx1-pf1.cudamail.com ([192.168.24.1]) by bar5.cudamail.com with ESMTP id PihREW7v5xMVtZg7 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 16 Feb 2016 04:22:45 -0700 (MST) X-Barracuda-Envelope-From: mark.b.kavanagh@intel.com X-Barracuda-RBL-Trusted-Forwarder: 192.168.24.1 Received: from unknown (HELO mga11.intel.com) (192.55.52.93) by mx1-pf1.cudamail.com with SMTP; 16 Feb 2016 11:22:45 -0000 Received-SPF: pass (mx1-pf1.cudamail.com: SPF record at intel.com designates 192.55.52.93 as permitted sender) X-Barracuda-Apparent-Source-IP: 192.55.52.93 X-Barracuda-RBL-IP: 192.55.52.93 Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga102.fm.intel.com with ESMTP; 16 Feb 2016 03:22:44 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,455,1449561600"; d="scan'208";a="747186430" Received: from sie-lab-214-146.ir.intel.com (HELO silpixa003830299.ir.intel.com) ([10.237.214.146]) by orsmga003.jf.intel.com with ESMTP; 16 Feb 2016 03:22:44 -0800 X-CudaMail-Envelope-Sender: mark.b.kavanagh@intel.com From: Mark Kavanagh To: dev@openvswitch.org, fbl@sysclose.org, diproiettod@vmware.com, aconole@redhat.com X-CudaMail-MID: CM-E1-215006972 X-CudaMail-DTE: 021616 X-CudaMail-Originating-IP: 192.55.52.93 Date: Tue, 16 Feb 2016 11:22:38 +0000 X-ASG-Orig-Subj: [##CM-E1-215006972##][PATCH V4 3/4] INSTALL.DPDK.md: add Jumbo Frames section Message-Id: <1455621759-93416-3-git-send-email-mark.b.kavanagh@intel.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1455621759-93416-2-git-send-email-mark.b.kavanagh@intel.com> References: <1455621759-93416-2-git-send-email-mark.b.kavanagh@intel.com> X-GBUdb-Analysis: 0, 192.55.52.93, Ugly c=0.271956 p=0 Source Normal X-MessageSniffer-Rules: 0-0-0-7779-c X-Barracuda-Connect: UNKNOWN[192.168.24.1] X-Barracuda-Start-Time: 1455621765 X-Barracuda-Encrypted: DHE-RSA-AES256-SHA X-Barracuda-URL: https://web.cudamail.com:443/cgi-mod/mark.cgi X-Virus-Scanned: by bsmtpd at cudamail.com X-Barracuda-BRTS-Status: 1 X-ASG-Whitelist: EmailCat (corporate) Subject: [ovs-dev] [PATCH V4 3/4] INSTALL.DPDK.md: add Jumbo Frames section X-BeenThere: dev@openvswitch.org X-Mailman-Version: 2.1.16 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dev-bounces@openvswitch.org Sender: "dev" Signed-off-by: Mark Kavanagh --- INSTALL.DPDK.md | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) diff --git a/INSTALL.DPDK.md b/INSTALL.DPDK.md index 722fb9e..4ca98cb 100644 --- a/INSTALL.DPDK.md +++ b/INSTALL.DPDK.md @@ -878,6 +878,60 @@ by adding the following string: to sections of all network devices used by DPDK. Parameter 'N' determines how many queues can be used by the guest. +Jumbo Frames +------------ + +Support for Jumbo Frames may be enabled at run-time for DPDK-type ports. + +To avail of Jumbo Frame support, add the 'mtu_request' option to the ovs-vsctl +'add-port' command-line, along with the required MTU for the port. +e.g. + + ``` + ovs-vsctl add-port br0 dpdk0 -- set Interface dpdk0 type=dpdk options:mtu_request=9000 + ``` + +When Jumbo Frames are enabled, the size of a DPDK port's mbuf segments are +increased, such that a full Jumbo Frame may be accommodated inside a single +mbuf segment. Once set, the MTU for a DPDK port is immutable. + +Note that from an OVSDB perspective, the `mtu_request` option for a specific +port may be disregarded once initially set, as subsequent modifications to this +field are disregarded by the DPDK port. As with non-DPDK ports, the MTU of DPDK +ports is reported by the `Interface` table's `mtu` field. + +Jumbo frame support has been validated against 13312B frames, using the +DPDK `igb_uio` driver, but larger frames and other DPDK NIC drivers may +theoretically be supported. Supported port types excludes vHost-Cuse ports, as +that feature is pending deprecation. + +vHost Ports and Jumbo Frames +---------------------------- +Jumbo frame support is available for DPDK vHost-User ports only. Some additional +configuration is needed to take advantage of this feature: + + 1. `mergeable buffers` must be enabled for vHost ports, as demonstrated in + the QEMU command line snippet below: + + ``` + '-netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce \' + '-device virtio-net-pci,mac=00:00:00:00:00:01,netdev=mynet1,mrg_rxbuf=on' + ``` + + 2. Where virtio devices are bound to the Linux kernel driver in a guest + environment (i.e. interfaces are not bound to an in-guest DPDK driver), the + MTU of those logical network interfaces must also be increased. This + avoids segmentation of Jumbo Frames in the guest. Note that 'MTU' refers + to the length of the IP packet only, and not that of the entire frame. + + e.g. To calculate the exact MTU of a standard IPv4 frame, subtract the L2 + header and CRC lengths (i.e. 18B) from the max supported frame size. + So, to set the MTU for a 13312B Jumbo Frame: + + ``` + ifconfig eth1 mtu 13294 + ``` + Restrictions: ------------- @@ -921,6 +975,11 @@ Restrictions: the next release of DPDK (which includes the above patch) is available and integrated into OVS. + Jumbo Frames: + - `virtio-pmd`: DPDK apps in the guest do not exit gracefully. This is a DPDK + issue that is currently being investigated. + - vHost-Cuse: Jumbo Frame support is not available for vHost Cuse ports. + Bug Reporting: --------------