From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH v8 10/10] app/testpmd:test VxLAN Tx checksum offload Date: Wed, 12 Nov 2014 18:26:07 +0100 Message-ID: <176980123.CbUgamS8oi@xps13> References: <1414376006-31402-1-git-send-email-jijiang.liu@intel.com> <5460E512.1050609@6wind.com> <1ED644BD7E0A5F4091CF203DAFB8E4CC01D8F7A7@SHSMSX101.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: dev-VfR2kkLFssw@public.gmane.org To: "Liu, Jijiang" Return-path: In-Reply-To: <1ED644BD7E0A5F4091CF203DAFB8E4CC01D8F7A7-0J0gbvR4kThpB2pF5aRoyrfspsVTdybXVpNB7YpNyf8@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" 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 checksums. > > > > > > 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 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. 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. Thanks -- Thomas