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From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: "Liu, Jijiang" <jijiang.liu@intel.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v6 1/9] librte_mbuf:the rte_mbuf structure changes
Date: Thu, 13 Nov 2014 12:35:15 +0100	[thread overview]
Message-ID: <5619154.Lqn3vQe6j1@xps13> (raw)
In-Reply-To: <1ED644BD7E0A5F4091CF203DAFB8E4CC01D9A425@SHSMSX101.ccr.corp.intel.com>

2014-11-13 11:24, Liu, Jijiang:
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > 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.
> 
> If needed, next week, I can send a patch for this.
> 
> > > 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?
> 
> We need some time to investigate this for igb/ixgbe, probably some
> example codes and test application codes need to changed. 
> You can assume that it cannot be done in DPDK1.8.
> 
> So here are my three suggestions:
> 
> 1. keep packet_type in mbuf and wait for all the igb/ixgb/i40e changes
> done in DPDK2.0. Now, I don't send a separate  patch set for it. 
> 2. keep  packet_type in mbuf, I just send i40e patch set for this in
> DPDK1.8. In DPDK2.0, we will send a patch set  for igb/ixgbe.
> 3. It can be removed now,  and we will send a separate patch set for
> introducing packet type in the future.

Option 2 please :)
My main concerns are:
- clearly document it
- have hardware abstraction

Thanks
-- 
Thomas

  reply	other threads:[~2014-11-13 11:25 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-21  8:45 [dpdk-dev] [PATCH v6 0/9] Support VxLAN on Fortville Jijiang Liu
2014-10-21  8:46 ` [dpdk-dev] [PATCH v6 1/9] librte_mbuf:the rte_mbuf structure changes Jijiang Liu
2014-10-21 10:26   ` Thomas Monjalon
2014-10-21 14:14     ` Liu, Jijiang
2014-10-22  8:45       ` Thomas Monjalon
2014-10-22  8:53         ` Liu, Jijiang
2014-10-23  2:23         ` Zhang, Helin
2014-11-12 13:26           ` Thomas Monjalon
2014-11-12 14:31             ` Zhang, Helin
2014-11-12 15:23               ` Thomas Monjalon
2014-11-13  3:17             ` Liu, Jijiang
2014-11-13  8:53               ` Thomas Monjalon
2014-11-13 11:24                 ` Liu, Jijiang
2014-11-13 11:35                   ` Thomas Monjalon [this message]
2014-10-21  8:46 ` [dpdk-dev] [PATCH v6 2/9] librte_ether:add VxLAN packet identification API in librte_ether Jijiang Liu
2014-10-21 10:51   ` Thomas Monjalon
2014-10-21 13:48     ` Liu, Jijiang
2014-10-21 21:19       ` Thomas Monjalon
2014-10-22  1:46         ` Liu, Jijiang
2014-10-22  9:52           ` Thomas Monjalon
2014-10-22 12:47             ` Liu, Jijiang
2014-10-22 13:25               ` Thomas Monjalon
2014-10-22  5:21         ` Liu, Jijiang
2014-10-21  8:46 ` [dpdk-dev] [PATCH v6 3/9] i40e:support VxLAN packet identification in librte_pmd_i40e Jijiang Liu
2014-10-21  8:46 ` [dpdk-dev] [PATCH v6 4/9] app/test-pmd:test VxLAN packet identification Jijiang Liu
2014-10-21  8:46 ` [dpdk-dev] [PATCH v6 5/9] librte_ether:add data structures of VxLAN filter Jijiang Liu
2014-10-21 15:13   ` Thomas Monjalon
2014-10-22  2:25     ` Liu, Jijiang
2014-10-22  9:31       ` Thomas Monjalon
2014-10-22 11:03         ` Liu, Jijiang
2014-10-23  9:06           ` Chilikin, Andrey
2014-10-22  6:45     ` Liu, Jijiang
2014-10-22  9:25       ` Thomas Monjalon
2014-10-22 13:54         ` Liu, Jijiang
2014-10-21  8:46 ` [dpdk-dev] [PATCH v6 6/9] i40e:implement API of VxLAN packet filter in librte_pmd_i40e Jijiang Liu
2014-10-21  8:46 ` [dpdk-dev] [PATCH v6 7/9] app/testpmd:test VxLAN packet filter Jijiang Liu
2014-10-21  8:46 ` [dpdk-dev] [PATCH v6 8/9] i40e:support VxLAN Tx checksum offload Jijiang Liu
2014-10-21  8:46 ` [dpdk-dev] [PATCH v6 9/9] app/testpmd:test " Jijiang Liu
2014-10-21 14:54 ` [dpdk-dev] [PATCH v6 0/9] Support VxLAN on Fortville Liu, Yong

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