From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by dpdk.org (Postfix) with ESMTP id A43337F25 for ; Fri, 14 Nov 2014 09:07:30 +0100 (CET) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP; 14 Nov 2014 00:14:46 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,384,1413270000"; d="scan'208";a="636857574" Received: from kmsmsx152.gar.corp.intel.com ([172.21.73.87]) by orsmga002.jf.intel.com with ESMTP; 14 Nov 2014 00:17:11 -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; Fri, 14 Nov 2014 16:15:47 +0800 Received: from shsmsx102.ccr.corp.intel.com (10.239.4.154) by pgsmsx105.gar.corp.intel.com (10.221.44.96) with Microsoft SMTP Server (TLS) id 14.3.195.1; Fri, 14 Nov 2014 16:15:47 +0800 Received: from shsmsx101.ccr.corp.intel.com ([169.254.1.110]) by shsmsx102.ccr.corp.intel.com ([169.254.2.216]) with mapi id 14.03.0195.001; Fri, 14 Nov 2014 16:15:46 +0800 From: "Liu, Jijiang" To: Thomas Monjalon Thread-Topic: [dpdk-dev] [PATCH v8 10/10] app/testpmd:test VxLAN Tx checksum offload Thread-Index: AQHP8Yux0VUY397yik2xjVM3DjesSpxPpsiAgAGaY5CAABv8AIAIEl8ggAAq4wCAAVxhEIAB236AgAFSGSD//7WkAIAB+JNw Date: Fri, 14 Nov 2014 08:15:45 +0000 Message-ID: <1ED644BD7E0A5F4091CF203DAFB8E4CC01D9B646@SHSMSX101.ccr.corp.intel.com> References: <1414376006-31402-1-git-send-email-jijiang.liu@intel.com> <176980123.CbUgamS8oi@xps13> <1ED644BD7E0A5F4091CF203DAFB8E4CC01D992F8@SHSMSX101.ccr.corp.intel.com> <3175184.TxKMqZeb6U@xps13> In-Reply-To: <3175184.TxKMqZeb6U@xps13> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 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: Fri, 14 Nov 2014 08:07:31 -0000 > -----Original Message----- > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com] > Sent: Thursday, November 13, 2014 5:10 PM > 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 >=20 > 2014-11-13 06:51, Liu, Jijiang: > > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com] > > > 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 th= e > > > > > > > driver use l2_len and l3_len to offload inner IP/UDP/TCP c= hecksums. > > > > > > > > > > > > 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 operatio= n. > > > > > > > > > > > > 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 > > > > tunneling 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, > > > depending 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 should set whole VXLAN packet TX checksum according to L3/L4 fl= ag > 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 no= t > only > > related to inner IP, but also IP. In other words, we use this one fla= g to > > set inner IP and outer IP checksum offload at the same time in driver, > > because it is not necessary to add other flag to stand for inner IP > > flag >=20 > You mean that PKT_TX_VXLAN_CKSUM request hardware checksumming of outer > L3, outer L4, inner L3 and inner L4? > So maybe the name and comments are not enough clear. Yes, PKT_TX_VXLAN_CKSUM request hardware checksum of outerL3, outer L4, inn= er L3 and inner L4. BTW, for outer UDP Checksum, generally, It SHOULD be transmitted as zero. = When a packet is received with a UDP checksum of zero, it MUST be accepted = for decapsulation. > > L4 flag usage is the same the L3 flag as well. >=20 > What do you mean? The PKT_TX_TCP_CKSUM, PKT_TX_SCTP_CKSUM, and PKT_TX_UDP_CKSUM flag are use= d to set TX checksum for outer L4 and inner for tunneling packet. But for VXLAN, outer L4 protocol must be UDP, so setting PKT_TX_TCP_CKSUM a= nd PKT_TX_SCTP_CKSUM is meaningless for outer L4. > > > 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 (encapsul= ation) > > * @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; >=20 > Yes it's a reference. But some things are made differently in DPDK. > Is there a flag PKT_TX_VXLAN_CKSUM in Linux? >=20 > I'm not sure what the checksumming API would be. > But I'm sure the VXLAN API is not enough commented. > Olivier is improving documentation of the legacy checksum API: > http://dpdk.org/ml/archives/dev/2014-November/007956.html > I'd like you do the same thing for VXLAN checksum. Ok , I will improve document about VXLAN checksum.=20 >=20 > Thanks > -- > Thomas