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
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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