From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id B600B595B for ; Thu, 13 Nov 2014 07:44:19 +0100 (CET) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP; 12 Nov 2014 22:54:14 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,375,1413270000"; d="scan'208,217";a="621643695" Received: from kmsmsx152.gar.corp.intel.com ([172.21.73.87]) by fmsmga001.fm.intel.com with ESMTP; 12 Nov 2014 22:53:49 -0800 Received: from pgsmsx105.gar.corp.intel.com (10.221.44.96) by KMSMSX152.gar.corp.intel.com (172.21.73.87) with Microsoft SMTP Server (TLS) id 14.3.195.1; Thu, 13 Nov 2014 14:51:15 +0800 Received: from shsmsx151.ccr.corp.intel.com (10.239.6.50) by pgsmsx105.gar.corp.intel.com (10.221.44.96) with Microsoft SMTP Server (TLS) id 14.3.195.1; Thu, 13 Nov 2014 14:51:15 +0800 Received: from shsmsx101.ccr.corp.intel.com ([169.254.1.110]) by SHSMSX151.ccr.corp.intel.com ([169.254.3.86]) with mapi id 14.03.0195.001; Thu, 13 Nov 2014 14:51:14 +0800 From: "Liu, Jijiang" To: Thomas Monjalon Thread-Topic: [dpdk-dev] [PATCH v8 10/10] app/testpmd:test VxLAN Tx checksum offload Thread-Index: AQHP8Yux0VUY397yik2xjVM3DjesSpxPpsiAgAGaY5CAABv8AIAIEl8ggAAq4wCAAVxhEIAB236AgAFSGSA= Date: Thu, 13 Nov 2014 06:51:13 +0000 Message-ID: <1ED644BD7E0A5F4091CF203DAFB8E4CC01D992F8@SHSMSX101.ccr.corp.intel.com> References: <1414376006-31402-1-git-send-email-jijiang.liu@intel.com> <5460E512.1050609@6wind.com> <1ED644BD7E0A5F4091CF203DAFB8E4CC01D8F7A7@SHSMSX101.ccr.corp.intel.com> <176980123.CbUgamS8oi@xps13> In-Reply-To: <176980123.CbUgamS8oi@xps13> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.15 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: Thu, 13 Nov 2014 06:44:20 -0000 > -----Original Message----- > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com] > Sent: Thursday, November 13, 2014 1:26 AM > To: Liu, Jijiang > Cc: dev@dpdk.org; Olivier MATZ > Subject: Re: [dpdk-dev] [PATCH v8 10/10] app/testpmd:test VxLAN Tx checks= um > offload > > 2014-11-11 05:29, Liu, Jijiang: > > From: Olivier MATZ > > > On 11/10/2014 07:03 AM, Liu, Jijiang wrote: > > > > > - if PKT_TX_VXLAN_CKSUM is not set (legacy use case), then the > > > > > driver use l2_len and l3_len to offload inner IP/UDP/TCP check= sums. > > > > > > > > If the flag is not set, and imply that it is not VXLAN packet, > > > > and do TX checksum offload as regular packet. > > > > > > > > > - if PKT_TX_VXLAN_CKSUM is set, then the driver has to use > > > > > inner_l{23}_len instead of l{23}_len for the same operation. > > > > > > > > Your understanding is not fully correct. > > > > The l{23}_len is still used for TX checksum offload, please refer > > > > to > > > > i40e_txd_enable_checksum() implementation. > > > > > > This fields are part of public mbuf API. You cannot say to refer to > > > i40e PMD code to understand how to use it. > > > > > > > > Adding PKT_TX_VXLAN_CKSUM changes the semantic of l2_len and > l3_len. > > > > > To fix this, I suggest to remove the new fields inner_l{23}_len > > > > > then add outer_l{23}_len instead. Therefore, the semantic of > > > > > l2_len and l3_len would not change, and a driver would always > > > > > use the same field for a specific offload. > > > > > > > > Oh... > > > > > > Does it mean you agree? > > > > I don't agree to change inner_l{23}_len the name. > > The reason is that using the "inner" word means incoming packet is tunn= eling > packet or encapsulation packet. > > if we add "outer"{2,3}_len, which will cause confusion when processing = non- > tunneling packet. > > Sorry Jijiang, maybe I don't understand what you are saying, but I think = you > missed something. Let me explain the problem. > > For PKT_TX_IP_CKSUM, we must set l{2,3}_len. > When PKT_TX_VXLAN_CKSUM is set, PKT_TX_IP_CKSUM is related to inner IP, > right? > So we must set inner_l{2,3}_len. > It means that PKT_TX_IP_CKSUM requires different fields to be set, depend= ing of > PKT_TX_VXLAN_CKSUM. That's what Olivier calls a semantic change. > It's not acceptable for an API. I'd like to explain what PKT_TX_VXLAN_CKSUM means, it is to tell driver sho= uld set whole VXLAN packet TX checksum according to L3/L4 flag setting. VXLAN packet IP checksum not only include inner IP, but also include outer= IP, so when PKT_TX_VXLAN_CKSUM is set, the PKT_TX_IP_CKSUM is not only re= lated to inner IP, but also IP. In other words, we use this one flag to s= et inner IP and outer IP checksum offload at the same time in driver, becau= se it is not necessary to add other flag to stand for inner IP flag L4 flag usage is the same the L3 flag as well. > PKT_TX_IP_CKSUM should always be related to l{2,3}_len. > When PKT_TX_VXLAN_CKSUM is set, we should add outer_l{2,3}_len. > Please, correct me if I'm wrong or fix the API. Probably we can refer to struct sk_buff in Linux kernel . Just as a reference!! struct sk_buff { ... * @inner_protocol: Protocol (encapsulation) * @inner_transport_header: Inner transport layer header (encapsulatio= n) * @inner_network_header: Network layer header (encapsulation) * @inner_mac_header: Link layer header (encapsulation) __u16 inner_transport_header; __u16 inner_network_header; __u16 inner_mac_header; __u16 transport_header; __u16 network_header; __u16 mac_header; > Thanks > Thomas