From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f180.google.com (mail-wi0-f180.google.com [209.85.212.180]) by dpdk.org (Postfix) with ESMTP id F0D127E9D for ; Wed, 12 Nov 2014 15:46:40 +0100 (CET) Received: by mail-wi0-f180.google.com with SMTP id hi2so5120985wib.13 for ; Wed, 12 Nov 2014 06:56:35 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:message-id:date:from:user-agent:mime-version:to :cc:subject:references:in-reply-to:content-type :content-transfer-encoding; bh=xK8m1bhEpHJQ8GDhH3hGmpZfRrLbV4WYAZh4/PXd+DU=; b=aFtFRgITsdXbRPK/HtqV3imEtZsTwAXDbFKluCtFyzWNeyW+KSPsyrnS0dUWsrvBcI XcHRSNdIi732fbTBa9UVfjbYAoljCDx+2UBoPBW/L0zF5rNV+UWUcv3yKfBari84YJRd ORUf4c6t6F5lGVBp1Eq3cTcUCiZvyeZZpR1qlaLO7s2xXJTAwqf2N9YgY6n7Dw2bngBX ZSsiUD34x6ffV/i5jSJiDBcIOyxC0P/u5WxMGwViPc5gRZimTP0RIshctjVaB3UhgTTZ 4SzqWomPgp7oJUCgmVgVjpJpF0uFlZp+wdLmTiyh1QmbdcChAkLb+5ADr2+lS2zJdr9d 2tcA== X-Gm-Message-State: ALoCoQlh+D66D9lzASC+YDjwDjj05tCWoTnY6U2OwS88Y4PaXr7xOz674bLfcwUEBjPdDh1Zr0d3 X-Received: by 10.194.157.65 with SMTP id wk1mr65382235wjb.9.1415804195530; Wed, 12 Nov 2014 06:56:35 -0800 (PST) Received: from [10.16.0.195] (guy78-3-82-239-227-177.fbx.proxad.net. [82.239.227.177]) by mx.google.com with ESMTPSA id b6sm21933068wiy.22.2014.11.12.06.56.34 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 12 Nov 2014 06:56:35 -0800 (PST) Message-ID: <54637521.9000709@6wind.com> Date: Wed, 12 Nov 2014 15:56:33 +0100 From: Olivier MATZ User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Icedove/24.5.0 MIME-Version: 1.0 To: "Ananyev, Konstantin" , Yong Wang , "Liu, Jijiang" References: <1414376006-31402-1-git-send-email-jijiang.liu@intel.com> <1414376006-31402-11-git-send-email-jijiang.liu@intel.com> <54588BF7.309@6wind.com> <1ED644BD7E0A5F4091CF203DAFB8E4CC01D8510E@SHSMSX101.ccr.corp.intel.com>, <5459FBB2.1040408@6wind.com> <0c654d2c0d304b45a40af6ca38b70adf@EX13-MBX-026.vmware.com> <545CFE56.60605@6wind.com> <2601191342CEEE43887BDE71AB977258213A38D2@IRSMSX105.ger.corp.intel.com> <5460E07F.6060303@6wind.com> <2601191342CEEE43887BDE71AB977258213A3F5F@IRSMSX105.ger.corp.intel.com> <54635B2B.5040603@6wind.com> <2601191342CEEE43887BDE71AB977258213A40EB@IRSMSX105.ger.corp.intel.com> In-Reply-To: <2601191342CEEE43887BDE71AB977258213A40EB@IRSMSX105.ger.corp.intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH v8 10/10] app/testpmd:test VxLAN Tx checksum offload X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 12 Nov 2014 14:46:41 -0000 Hi Konstantin, On 11/12/2014 03:39 PM, Ananyev, Konstantin wrote: >> I'm not sure having get_ipv4_udptcp_checksum() in librte_net would >> help. The value we have to set in the TCP checksum field depends on the >> PMD (altought only ixgbe is supported now). So, it would require >> another parameter and a new PMD eth_ops... which looks very >> similar to dev_prep_tx() (except that dev_prep_tx() can be bulked). >> I think a stack will not be able to call get_udptcp_checksum(m ,port) >> because it does not know the physical port at the time the packet is >> built. Moreover, calling a function through a pointer is more efficient >> when bulked. So I think the dev_prep_tx() you initially describe is >> a better answer to the problem. > > Yes I understand that it might not be applicable for non-Intel NICs. > Though I thought it is ok as a temporary measure as right now we > support these offloads for Intel NICs only. > Basically my thought was what you proposed as option 3 below. > Why common function in librte_net? > So people don't need to write their own each time. > Plus as I remember all 3 Intel NIC types (ixgbe/igb/i40e) we support have similar > requirements for what need to be set/calculated for these TX offloads. > So my thought was that having a common function might help to avoid code duplication in future, > If/when will implement dev_prep_tx(). OK, now I understand better what you suggest. I'll try to implement the option 3 (below) with a common checksum function in librte_net in the next version of the TSO patchset. Regards, Olivier > >> >> I don't know what is the exact timeframe for 1.8, maybe Thomas can help >> on this? Depending on it, we have several options: >> >> - implement dev_prep_tx() for 1.8 in the TSO series: this implies that >> the community agrees on this new API. We need to check that it will >> be faster in a pipeline model (I think this is obvious) but also that >> it does not penalize the run-to-completion model: introducing another >> function dev_prep_tx() can result in duplicated tests in the driver >> (ex: test the offload flag values). >> >> - postpone dev_prep_tx() or similar to next version and push the current >> TSO patchset (including the comments done on the list). It does not >> modify the current offload API, it provides the TSO feature on ixgbe >> based on a similar API concept (set the TCP phdr cksum). The drawback >> is a potential performance loss when using a pipeline model. >> >> - another option that you may prefer is to bind the API behavior to >> ixgbe (for 1.8): we can ask the application to set the pseudo-header >> checksum without the IP len when doing TSO, as required by the ixgbe >> driver. Then, for next release, we can think about dev_prep_tx(). The >> drawback of this solution is that we may go back on this choice if the >> dev_prep_tx() approach is not validated by the community.