DPDK patches and discussions
 help / color / mirror / Atom feed
From: "Liu, Jijiang" <jijiang.liu@intel.com>
To: Olivier MATZ <olivier.matz@6wind.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v8 10/10] app/testpmd:test VxLAN Tx checksum offload
Date: Thu, 6 Nov 2014 14:27:16 +0000
Message-ID: <1ED644BD7E0A5F4091CF203DAFB8E4CC01D85962@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <545B72E5.9090002@6wind.com>

Hi Olivier,

> -----Original Message-----
> From: Olivier MATZ [mailto:olivier.matz@6wind.com]
> Sent: Thursday, November 6, 2014 9:09 PM
> To: Liu, Jijiang
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v8 10/10] app/testpmd:test VxLAN Tx checksum
> offload
> 
> Hello Jijiang,
> 
> On 11/06/2014 12:24 PM, Liu, Jijiang wrote:
> >> Is it possible to have a more formal definition? For instance, is the
> >> following definition below correct?
> >>
> >>   "the PKT_RX_TUNNEL_IPV4_HDR flag CAN be set by a driver if the packet
> >>    contains a tunneling protocol inside an IPv4 header".
> >
> > Yes, correct.
> >
> >> If the definition above is correct, I don't see how this flag can
> >> help an application to run faster. There is already a flag telling if
> >> there is a valid IPv4 header (PKT_RX_IPV4_HDR). As the
> >> PKT_RX_TUNNEL_IPV4_HDR flag does not tell what is ip->proto, the work
> >> done by an application to dissect a packet would be exactly the same with or
> without this flag.
> >
> > If the PKT_RX_TUNNEL_IPV4_HDR flag is set, which means driver tell
> application that incoming packet is encapsulated packet, and application will
> process / analyse the packet according to tunneling format indicated by
> packet_type.
> 
> Where is it written that when the PKT_RX_TUNNEL_IPV4_HDR flag is set, the
> packet_type is also set?
> 
> To which header packet_type refers to? Inner or Outer? Depends?
> 
> What are the possible values for packet_type?
> 
> Is the PKT_RX_TUNNEL_IPV4_HDR flag set in mbuf related to the commands
> rx_vxlan_port add|del? If yes, it should be written in the API!
> (assuming this is the right API design)
> 
> When the PKT_RX_TUNNEL_IPV4_HDR flag is set, does PKT_RX_IPV4_HDR or
> PKT_RX_VLAN_PKT concerns the inner or outer headers? I hope it still concerns
> the first one, else it would break many applications relying on the these flags.
> 
> As you can see, today, an application cannot use PKT_RX_TUNNEL_IPV4_HDR or
> m->packet_type because it is not documented.
> 
> 
> > In terms of VXLAN packet format (MAC,IPv4,UDP,VXLAN,MAC,IP,TCP,PAY4), if
> only the PKT_RX_IPV4_HDR flag is set, and application regard its payload as "from
> VXLAN to PAY4", but actually, the real payload is PAY4.
> >
> >> Please, can you give an example showing in which conditions this flag
> >> can help an application?
> >
> > http://dpdk.org/ml/archives/dev/2014-October/007151.html
> > http://dpdk.org/ml/archives/dev/2014-October/007156.html
> >
> > We used the PKT_RX_TUNNEL_IPV4_HDR in the two patches to help
> application identify incoming packet is tunneling packet.
> 
> As you agreed on "the PKT_RX_TUNNEL_IPV4_HDR flag CAN be set by a driver",
> it means that if the flag is not present, the application should do the check in
> software. And there are several reasons why the flag may not be present:
>  - the packet is not a VxLAN packet
As long as it is tunneling packet with IPv4/6 header, the flag should be set by driver.

>  - the hw or driver was not able to recognize it (I don't know, maybe
>    if there are IP options the hw will not recognize it?) 
>  - the hw or driver does not support it (all drivers except i40e)
E1000/ixgbe don't support VXLAN packet and another tunneling packet, so driver don't need to set this flag.
As to other NICs that support tunneling packet , I don't why HW or driver can't recognize it.

> So the application has to provide the software equivalent code to process PAY4.
> 
> The "csum" testpmd forwarding engine is now a bad example because it is not
> able to do the same processing in software or hardware. It now only works with
> an i40e driver, which was not the case before. Also, the semantic of the command
> line arguments changed. Before, the meaning was "if the flag is set, process the
> checksum in the NIC, else in SW".
> Now, it's "huh... it depends on the flag."


Currently, If the packet is non-tunneling packet, I believe the  "csum" testpmd forwarding engine also works well as before.
we changed the engine as follows, which is compatible with previous implementation.
-		if (pkt_ol_flags & PKT_RX_IPV4_HDR) {
+		if (pkt_ol_flags & (PKT_RX_IPV4_HDR | PKT_RX_TUNNEL_IPV4_HDR)) {
...

-		else if (pkt_ol_flags & PKT_RX_IPV6_HDR) {
+		} else if (pkt_ol_flags & (PKT_RX_IPV6_HDR | PKT_RX_TUNNEL_IPV6_HDR)) {


> I will submit a rework of the csum fowarding engine to clarify its behavior.
OK. good.

> Regards,
> Olivier

  reply	other threads:[~2014-11-06 14:17 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-27  2:13 [dpdk-dev] [PATCH v8 00/10] Support VxLAN on Fortville Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 01/10] librte_mbuf:the rte_mbuf structure changes Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 02/10] librte_ether:add the basic data structures of VxLAN Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 03/10] librte_ether:add VxLAN packet identification API Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 04/10] i40e:support VxLAN packet identification in i40e Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 05/10] app/test-pmd:test VxLAN packet identification Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 06/10] librte_ether:add data structures of VxLAN filter Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 07/10] i40e:implement the API of VxLAN filter in librte_pmd_i40e Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 08/10] app/testpmd:test VxLAN packet filter Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 09/10] i40e:support VxLAN Tx checksum offload Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 10/10] app/testpmd:test " Jijiang Liu
2014-11-04  8:19   ` Olivier MATZ
2014-11-05  6:02     ` Liu, Jijiang
2014-11-05 10:28       ` Olivier MATZ
2014-11-06 11:24         ` Liu, Jijiang
2014-11-06 13:08           ` Olivier MATZ
2014-11-06 14:27             ` Liu, Jijiang [this message]
2014-11-07  0:43         ` Yong Wang
2014-11-07 17:16           ` Olivier MATZ
2014-11-10 11:39             ` Ananyev, Konstantin
2014-11-10 15:57               ` Olivier MATZ
2014-11-12  9:55                 ` Ananyev, Konstantin
2014-11-12 13:05                   ` Olivier MATZ
2014-11-12 13:40                     ` Thomas Monjalon
2014-11-12 23:14                       ` Ananyev, Konstantin
2014-11-12 14:39                     ` Ananyev, Konstantin
2014-11-12 14:56                       ` Olivier MATZ
     [not found]             ` <D0868B54.24DBB%yongwang@vmware.com>
2014-11-11  0:07               ` [dpdk-dev] FW: " Yong Wang
2014-11-10  6:03         ` [dpdk-dev] " Liu, Jijiang
2014-11-10 16:17           ` Olivier MATZ
     [not found]             ` <1ED644BD7E0A5F4091CF203DAFB8E4CC01D8F7A7@SHSMSX101.ccr.corp.intel.com>
2014-11-12 17:26               ` Thomas Monjalon
2014-11-13  5:35                 ` Liu, Jijiang
2014-11-13  5:39                   ` Liu, Jijiang
2014-11-13  6:51                 ` Liu, Jijiang
2014-11-13  9:10                   ` Thomas Monjalon
2014-11-14  8:15                     ` Liu, Jijiang
2014-11-14  9:09                       ` Olivier MATZ
2014-11-17  6:52                         ` Liu, Jijiang
2014-11-17 11:21                           ` Olivier MATZ
2014-11-20  7:28                             ` Liu, Jijiang
2014-11-20 16:36                               ` Olivier MATZ
2014-11-21  5:40                                 ` Liu, Jijiang
2014-10-27  2:20 ` [dpdk-dev] [PATCH v8 00/10] Support VxLAN on Fortville Liu, Yong
2014-10-27  2:41 ` Zhang, Helin
2014-10-27 13:46   ` Thomas Monjalon
2014-10-27 14:34     ` Liu, Jijiang
2014-10-27 15:15       ` Thomas Monjalon

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=1ED644BD7E0A5F4091CF203DAFB8E4CC01D85962@SHSMSX101.ccr.corp.intel.com \
    --to=jijiang.liu@intel.com \
    --cc=dev@dpdk.org \
    --cc=olivier.matz@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

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ https://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git