From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olivier MATZ Subject: Re: [PATCH v2] pmd: Add generic support for TCP TSO (Transmit Segmentation Offload) Date: Fri, 31 Oct 2014 16:49:44 +0100 Message-ID: <5453AF98.8060502@6wind.com> References: <20141021112946.30069.67329.stgit@gklab-18-011.igk.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit To: miroslaw.walukiewicz-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, dev-VfR2kkLFssw@public.gmane.org Return-path: In-Reply-To: <20141021112946.30069.67329.stgit-tpi2AMbES9qir5R1eWH9hGt3HXsI98Cx0E9HWUfgJXw@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" Hello Miroslaw, On 10/21/2014 01:29 PM, miroslaw.walukiewicz-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org wrote: > From: Miroslaw Walukiewicz > > The NICs supported by DPDK have a possibility to accelerate TCP > traffic by sergnention offload. The application preprares a packet > with valid TCP header with size up to 64K and NIC makes packet > segmenation generating valid checksums and TCP segments. > > The patch defines a generic support for TSO offload. > - Add new PKT_TX_TCP_SEG flag. > Only packets with this flag set in ol_flags will be handled as > TSO packets. > > - Add new fields in indicating TCP TSO segment size and TCP header len. > The TSO requires from application setting following fields in mbuf. > 1. L2 header len including MAC/VLANs/SNAP if present > 2. L3 header len including IP options > 3. L4 header len (new field) including TCP options > 4. tso_segsz (new field) the size of TCP segment > > The apllication has obligation to compute the pseudo header checksum > instead of full TCP checksum and put it in the TCP header csum field. > > Handling complexity of creation combined l2_l3_len field > a new macro RTE_MBUF_TO_L2_L3_LEN() is defined to retrieve this > part of rte_mbuf. > The patch you submitted does not include any changes in a driver (let's say ixgbe as it is the reference) taking advantage it. So it's difficult to validate that your modifications are sufficient to implement TSO. In addition of a driver, I think that testpmd should be modified to validate your changes and give an example to people wanting to use this feature. Based on your patch, I'll try to submit a series in the coming days (maybe today if the winds are favourable) that includes the remaining patches from the original TSO series [1] that were not applied by Bruce's mbuf rework. Regards, Olivier [1] http://dpdk.org/ml/archives/dev/2014-May/002537.html