DPDK patches and discussions
 help / color / mirror / Atom feed
From: "Zhang, Helin" <helin.zhang@intel.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>,
	"Liu, Jijiang" <jijiang.liu@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v6 1/9] librte_mbuf:the rte_mbuf structure changes
Date: Wed, 12 Nov 2014 14:31:50 +0000	[thread overview]
Message-ID: <F35DEAC7BCE34641BA9FAC6BCA4A12E70A7BC2F2@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <2835075.ZIuhO63ZWU@xps13>



> -----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
> 
> Hi guys,
> 
> We still have some problems with the mbuf changes introduced for VXLAN.
> I want to raise the packet type issue here.
> 
> 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 padding */
> > > > > > +
> > > > > > +	/**
> > > > > > +	 * Packet type, which is used to indicate ordinary L2 packet
> format and
> > > > > > +	 * also tunneled packet format such as IP in IP, IP in GRE, MAC 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 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
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.

> 
> 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).
> 
> --
> Thomas

Regards,
Helin

  reply	other threads:[~2014-11-12 14:22 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 [this message]
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
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=F35DEAC7BCE34641BA9FAC6BCA4A12E70A7BC2F2@SHSMSX104.ccr.corp.intel.com \
    --to=helin.zhang@intel.com \
    --cc=dev@dpdk.org \
    --cc=jijiang.liu@intel.com \
    --cc=thomas.monjalon@6wind.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).