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 [thread overview]
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
next prev parent 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
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