From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 66DCF7F2C for ; Wed, 12 Nov 2014 15:22:03 +0100 (CET) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga103.fm.intel.com with ESMTP; 12 Nov 2014 06:25:21 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,862,1389772800"; d="scan'208";a="415417914" Received: from kmsmsx151.gar.corp.intel.com ([172.21.73.86]) by FMSMGA003.fm.intel.com with ESMTP; 12 Nov 2014 06:22:56 -0800 Received: from pgsmsx105.gar.corp.intel.com (10.221.44.96) by KMSMSX151.gar.corp.intel.com (172.21.73.86) with Microsoft SMTP Server (TLS) id 14.3.195.1; Wed, 12 Nov 2014 22:31:53 +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; Wed, 12 Nov 2014 22:31:52 +0800 Received: from shsmsx104.ccr.corp.intel.com ([169.254.5.62]) by shsmsx102.ccr.corp.intel.com ([169.254.2.136]) with mapi id 14.03.0195.001; Wed, 12 Nov 2014 22:31:51 +0800 From: "Zhang, Helin" To: Thomas Monjalon , "Liu, Jijiang" Thread-Topic: [dpdk-dev] [PATCH v6 1/9] librte_mbuf:the rte_mbuf structure changes Thread-Index: AQHP/oVlSrakVePwpUusuby3skYHiw== Date: Wed, 12 Nov 2014 14:31:50 +0000 Message-ID: References: <1413881168-20239-1-git-send-email-jijiang.liu@intel.com> <1710340.mrZid3JfsP@xps13> <2835075.ZIuhO63ZWU@xps13> In-Reply-To: <2835075.ZIuhO63ZWU@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 v6 1/9] librte_mbuf:the rte_mbuf structure changes 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: Wed, 12 Nov 2014 14:22:04 -0000 > -----Original Message----- > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com] > Sent: Wednesday, November 12, 2014 9:26 PM > To: Liu, Jijiang > Cc: Zhang, Helin; dev@dpdk.org; Richardson, Bruce > Subject: Re: [dpdk-dev] [PATCH v6 1/9] librte_mbuf:the rte_mbuf structure > changes >=20 > Hi guys, >=20 > We still have some problems with the mbuf changes introduced for VXLAN. > I want to raise the packet type issue here. >=20 > 2014-10-23 02:23, Zhang, Helin: > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Thomas Monjalon > > > 2014-10-21 14:14, Liu, Jijiang: > > > > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com] > > > > > 2014-10-21 16:46, Jijiang Liu: > > > > > > - uint16_t reserved2; /**< Unused field. Required for pad= ding */ > > > > > > + > > > > > > + /** > > > > > > + * Packet type, which is used to indicate ordinary L2 packet > format and > > > > > > + * also tunneled packet format such as IP in IP, IP in GRE, M= AC in > GRE > > > > > > + * and MAC in UDP. > > > > > > + */ > > > > > > + uint16_t packet_type; > > > > > > > > > > Why not name it "l2_type"? > > > > 'packet_type' is for storing the hardware identified packet type upon > > different layers of protocols (l2, l3, l4, ...). > > It is quite useful for user application or middle layer software > > stacks, it can know what the packet type is without checking the packet= too > much by software. > > Actually ixgbe already has packet types (less than 10), which is transc= oded into > 'ol_flags'. > > For i40e, the packet type can represent about 256 types of packet, > > 'ol_flags' does not have enough bits for it anymore. So put the i40e pa= cket > types into mbuf would be better. > > Also this field can be used for NON-Intel NICs, I think there must be > > the similar concepts of other NICs. And 16 bits 'packet_type' has sever= l > reserved bits for future and NON-Intel NICs. >=20 > Thanks Helin, that's the best description of packet_type I've seen so far= . > It's not so clear in the commit log: > http://dpdk.org/browse/dpdk/commit/?id=3D73b7d59cf4f6faf >=20 > > > > In datasheet, this term is called packet type(s). > > > > > > That's exactly the point I want you really understand! > > > This is a field in generic mbuf structure, so your datasheet has no v= alue here. > > > > > > > Personally , I think packet type is more clear what meaning of thi= s field is . > > > > > > You cannot add an API field without knowing what will be its generic = meaning. > > > Please think about it and describe its scope. >=20 > I integrated this patch with the VXLAN patchset in the hope that you'll i= mprove > the situation afterwards. > This is the answer you recently gave to Olivier: > http://dpdk.org/ml/archives/dev/2014-November/007599.html > " > Regarding adding a packet_type in mbuf, we ever had a lot of discussions= as > follows: > http://dpdk.org/ml/archives/dev/2014-October/007027.html > http://dpdk.org/ml/archives/dev/2014-September/005240.html > http://dpdk.org/ml/archives/dev/2014-September/005241.html > http://dpdk.org/ml/archives/dev/2014-September/005274.html > " >=20 > To sum up the situation: > - We don't know what are the possible values of packet_type > - It's only filled by i40e, while other drivers use ol_flags > - There is no special value "unknown" which should be set by drivers > not supporting this feature. > - Its only usage is to print a decimal value in app/test-pmd/rxonly.c Though I haven't investigate this too much, my opinion is that we should use packet_type in the future, and rework igb/ixgbe PMD to remove all packet types in ol_flags and use packet_type instead. Then example app can use the packet type directly. And all igb, ixgbe and i40e packet_type are consistent. Sure we might need to define all packet types in rte_ethdev.h or similar header files. >=20 > It's now clear that nobody cares about this part of the API. > So I'm going to remove packet_type from mbuf. > I don't want to keep something that we don't know how to use, that is not > consistent across drivers, and that overlap another API part (ol_flags). >=20 > -- > Thomas Regards, Helin