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[109.190.92.136]) by mx.google.com with ESMTPSA id bl9sm24799383wib.24.2014.11.13.00.53.34 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Nov 2014 00:53:34 -0800 (PST) From: Thomas Monjalon To: "Liu, Jijiang" Date: Thu, 13 Nov 2014 09:53:17 +0100 Message-ID: <6349776.LhCYQBaBlF@xps13> Organization: 6WIND User-Agent: KMail/4.14.2 (Linux/3.17.2-1-ARCH; KDE/4.14.2; x86_64; ; ) In-Reply-To: <1ED644BD7E0A5F4091CF203DAFB8E4CC01D97183@SHSMSX101.ccr.corp.intel.com> References: <1413881168-20239-1-git-send-email-jijiang.liu@intel.com> <2835075.ZIuhO63ZWU@xps13> <1ED644BD7E0A5F4091CF203DAFB8E4CC01D97183@SHSMSX101.ccr.corp.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" 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: Thu, 13 Nov 2014 08:43:38 -0000 2014-11-13 03:17, Liu, Jijiang: > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com] > > 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 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 transcoded 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 packet 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 severl > > reserved bits for future and NON-Intel NICs. > > > > 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=73b7d59cf4f6faf > > > > > > > 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 value here. > > > > > > > > > Personally , I think packet type is more clear what meaning of this field is . > > > > > > > > You cannot add an API field without knowing what will be its generic meaning. > > > > Please think about it and describe its scope. > > > > I integrated this patch with the VXLAN patchset in the hope that you'll improve > > 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 > > " > > > > 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 > > > > 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). > > The packet type in 40e is very important for user, using packet type can > help to speed up packet analysis/identification in their application, > especially tunneling packet format. > Now I'm working on implementing packet type definition in rte_ethdev.h > file and translation table in i40e, which is almost done. > The packet type definition in in rte_ethdev.h file like below. > /* > * Ethernet packet type > */ > enum rte_eth_ptype { > /* undefined packet type, means HW can't recognise it */ > RTE_PTYPE_UNDEF = 0, > ... > > /* IPv4 --> GRE/Teredo/VXLAN --> MAC --> IPv4 */ > RTE_PTYPE_IPv4_GRENAT_MAC_IPv4FRAG_PAY3, > RTE_PTYPE_IPv4_GRENAT_MAC_IPv4_PAY3, > RTE_PTYPE_IPv4_GRENAT_MAC_IPv4_UDP_PAY4, > RTE_PTYPE_IPv4_GRENAT_MAC_IPv4_TCP_PAY4, > RTE_PTYPE_IPv4_GRENAT_MAC_IPv4_SCTP_PAY4, > RTE_PTYPE_IPv4_GRENAT_MAC_IPv4_ICMP_PAY4, > > /* IPv4 --> GRE/Teredo/VXLAN --> MAC --> IPv6 */ > RTE_PTYPE_IPv4_GRENAT_MAC_IPv6FRAG_PAY3 > RTE_PTYPE_IPv4_GRENAT_MAC_IPv6_PAY3, > RTE_PTYPE_IPv4_GRENAT_MAC_IPv6_UDP_PAY4, > RTE_PTYPE_IPv4_GRENAT_MAC_IPv6_TCP_PAY4, > RTE_PTYPE_IPv4_GRENAT_MAC_IPv6_SCTP_PAY4, > RTE_PTYPE_IPv4_GRENAT_MAC_IPv6_ICMP_PAY4, > > /* IPv4 --> GRE/Teredo/VXLAN --> MAC/VLAN */ > RTE_PTYPE_IPv4_GRENAT_MACVLAN_PAY3, > ... > } OK, it seems well abstracted. I think the last part of these names (PAY3/PAY4) is useless. When this patch for API and i40e will be ready? I'd prefer fixing the API instead of removing it. > Yes, we don't use packet type in many places now, which doesn't mean > we don't use it in the future (when supporting another tunneling packet). > > It is ok for me if you want to remove the packet_type filed in mbuf, > but we will send a separate patch set for introducing packet type in > the future, which includes 1g/10/40g PMD changes. When the patches for igb/ixgbe will be ready? Thanks -- Thomas