From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <venky.venkatesan@intel.com> Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id 492D7591A for <dev@dpdk.org>; Wed, 27 May 2015 17:30:24 +0200 (CEST) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP; 27 May 2015 08:30:23 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,506,1427785200"; d="scan'208";a="732538884" Received: from orsmsx105.amr.corp.intel.com ([10.22.225.132]) by fmsmga002.fm.intel.com with ESMTP; 27 May 2015 08:30:24 -0700 Received: from orsmsx151.amr.corp.intel.com (10.22.226.38) by ORSMSX105.amr.corp.intel.com (10.22.225.132) with Microsoft SMTP Server (TLS) id 14.3.224.2; Wed, 27 May 2015 08:30:22 -0700 Received: from orsmsx102.amr.corp.intel.com ([169.254.1.45]) by ORSMSX151.amr.corp.intel.com ([169.254.7.160]) with mapi id 14.03.0224.002; Wed, 27 May 2015 08:30:22 -0700 From: "Venkatesan, Venky" <venky.venkatesan@intel.com> To: "Wiles, Keith" <keith.wiles@intel.com>, Lin XU <lxu@astri.org>, "dev@dpdk.org" <dev@dpdk.org> Thread-Topic: [dpdk-dev] proposal: raw packet send and receive API for PMD driver Thread-Index: AQHQmIyEdvTN/E8PiUuVC401KnNyBZ2P7WKQ Date: Wed, 27 May 2015 15:30:22 +0000 Message-ID: <1FD9B82B8BF2CF418D9A1000154491D9744CD75D@ORSMSX102.amr.corp.intel.com> References: <D18B41D3.20FDE%keith.wiles@intel.com> In-Reply-To: <D18B41D3.20FDE%keith.wiles@intel.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.22.254.139] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] proposal: raw packet send and receive API for PMD driver X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK <dev.dpdk.org> List-Unsubscribe: <http://dpdk.org/ml/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://dpdk.org/ml/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <http://dpdk.org/ml/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> X-List-Received-Date: Wed, 27 May 2015 15:30:25 -0000 > -----Original Message----- > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Wiles, Keith > Sent: Wednesday, May 27, 2015 7:51 AM > To: Lin XU; dev@dpdk.org > Subject: Re: [dpdk-dev] proposal: raw packet send and receive API for PMD > driver >=20 >=20 >=20 > On 5/26/15, 11:18 PM, "Lin XU" <lxu@astri.org> wrote: >=20 > >I think it is very important to decouple PMD driver with DPDK framework. > > (1) Currently, the rte_mbuf struct is too simple and hard to support > >complex application such as IPSEC, flow control etc. This key struct > >should be extendable to support customer defined management header > and > >hardware offloading feature. >=20 > I was wondering if adding something like M_EXT support for external stora= ge > to DPDK MBUF would be more reasonable. >=20 > IMO decoupling PMDs from DPDK will possible impact performance and I > would prefer not to let this happen. The drivers are written for performa= nce, > but they did start out as normal FreeBSD/Linux drivers. Most of the core > code to the Intel drivers are shared between other systems. >=20 This was an explicit design choice to keep the mbuf simple, yet sufficient = to service volume NIC controllers and the limited offloads that they have. = I would prefer not to have rte_mbuf burdened with all that a protocol stack= needs - that will simply increase the size of the structure and penalize a= pplications that need a lean structure (like security applications). Extend= ing the mbuf to 128 bytes itself caused a regression in some performance ap= ps.=20 That said, extensibility or for that matter a custom defined header is poss= ible with in at least two ways.=20 a) the userdata pointer field can be set to point to a data structure that = contains more information b) you could simply embed the custom structure (like the pipeline code does= ) behind the rte_mbuf These can be used to pass through any information from NICs that support ha= rdware offloads as well as carrying areas for protocol stack specific infor= mation (e.g. complete IPSEC offload).=20 > > (2) To support more NICs. > >So, I thinks it time to add new API for PMD(a no radical way), and > >developer can add initial callback function in PMD for various upper > >layer protocol procedures. >=20 > We have one callback now I think, but what callbacks do you need? >=20 > The only callback I can think of is for a stack to know when it can relea= se its > hold on the data as it has been transmitted for retry needs. > > > > The one place that I do think we need to change is the memory allocation fr= amework - allowing external memory allocators (buf alloc/free) so that the = driver could be run within a completely different memory allocator system. = It can be done with the system we have in place today with specific overrid= es, but it isn't simple. I think there was another request along similar l= ines on the list. This would pretty much allow a TCP stack for example to a= llocate and manage memory (as long as the driver interface via an MBUF can = be maintained). If this is something valuable, we could look at pursuing t= his for the next release.=20 -Venky