From patchwork Wed Nov 1 02:45:28 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wenzhuo Lu X-Patchwork-Id: 31072 X-Patchwork-Delegate: ferruh.yigit@amd.com 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 B47F81B221; Wed, 1 Nov 2017 03:44:06 +0100 (CET) Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by dpdk.org (Postfix) with ESMTP id 0DEB21B219 for ; Wed, 1 Nov 2017 03:44:04 +0100 (CET) Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga104.jf.intel.com with ESMTP; 31 Oct 2017 19:44:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos; i="5.44,326,1505804400"; d="scan'208"; a="1031907364" Received: from dpdk26.sh.intel.com ([10.67.110.152]) by orsmga003.jf.intel.com with ESMTP; 31 Oct 2017 19:44:02 -0700 From: Wenzhuo Lu To: dev@dpdk.org Cc: Wenzhuo Lu Date: Wed, 1 Nov 2017 10:45:28 +0800 Message-Id: <1509504328-111123-1-git-send-email-wenzhuo.lu@intel.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1508900093-9894-1-git-send-email-wenzhuo.lu@intel.com> References: <1508900093-9894-1-git-send-email-wenzhuo.lu@intel.com> Subject: [dpdk-dev] [PATCH v3] doc: more clarification for i40e 16 byte desc 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" The description of i40e 16 byte descriptor is not clear enough. Add more details. Signed-off-by: Wenzhuo Lu Acked-by: Bruce Richardson --- doc/guides/nics/i40e.rst | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/doc/guides/nics/i40e.rst b/doc/guides/nics/i40e.rst index a0946e6..05c1875 100644 --- a/doc/guides/nics/i40e.rst +++ b/doc/guides/nics/i40e.rst @@ -398,13 +398,24 @@ used to classify MPLS packet by using a command in testpmd like: testpmd> ethertype_filter 0 add mac_ignr 00:00:00:00:00:00 ethertype \ 0x8847 fwd queue -16 Byte Descriptor cannot be used on DPDK VF -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +16 Byte RX Descriptor setting on DPDK VF +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -If the Linux i40e kernel driver is used as host driver, while DPDK i40e PMD -is used as the VF driver, DPDK cannot choose 16 byte receive descriptor. That -is to say, user should keep ``CONFIG_RTE_LIBRTE_I40E_16BYTE_RX_DESC=n`` in -config file. +Currently the VF's RX descriptor mode is decided by PF. There's no PF-VF +interface for VF to request the RX descriptor mode, also no interface to notify +VF its own RX descriptor mode. +For all available versions of the i40e driver, these drivers don't support 16 +byte RX descriptor. If the Linux i40e kernel driver is used as host driver, +while DPDK i40e PMD is used as the VF driver, DPDK cannot choose 16 byte receive +descriptor. The reason is that the RX descriptor is already set to 32 byte by +the i40e kernel driver. That is to say, user should keep +``CONFIG_RTE_LIBRTE_I40E_16BYTE_RX_DESC=n`` in config file. +In the future, if the Linux i40e driver supports 16 byte RX descriptor, user +should make sure the DPDK VF uses the same RX descriptor mode, 16 byte or 32 +byte, as the PF driver. + +The same rule for DPDK PF + DPDK VF. The PF and VF should use the same RX +descriptor mode. Or the VF RX will not work. Receive packets with Ethertype 0x88A8 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~