> -----Original Message----- > From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com] > Sent: Friday, December 05, 2014 4:07 PM > To: Liu, Jijiang > Cc: dev at dpdk.org; Ananyev, Konstantin; olivier.matz at 6wind.com > Subject: Re: [dpdk-dev] [PATCH v5 0/3] i40e VXLAN TX checksum rework > > > > We have got some feedback about backward compatibility of VXLAN TX > > > checksum offload API with 1G/10G NIC after the i40e > VXLAN > > > TX checksum codes were applied, so we have to rework the APIs on i40e, > > > including the changes of mbuf, i40e PMD and csum > forward > > > engine. > > > > > > The main changes in mbuf are as follows, in place of removing > > > PKT_TX_VXLAN_CKSUM, we introduce 4 new flags: > > > PKT_TX_OUTER_IP_CKSUM, PKT_TX_OUTER_IPV4, PKT_TX_OUTER_IPV6 and > > > PKT_TX_UDP_TUNNEL_PKT. Replace the > inner_l2_len > > > and the inner_l3_len field with the outer_l2_len and outer_l3_len field. > > > > > > Let's use a few examples to demonstrate how to use these new flags and > > > existing flags in rte_mbuf.h > > > Let say we have a tunnel packet: > > > eth_hdr_out/ipv4_hdr_out/udp_hdr_out/vxlan_hdr/ehtr_hdr_in/ipv4_hdr_in/tcp_hdr_in. > There > > > could be several scenarios: > > > > > > A) User requests HW offload for ipv4_hdr_out checksum. > > > He doesn't care is it a tunnelled packet or not. So he sets: > > > > > > mb->l2_len = eth_hdr_out; > > > mb->l3_len = ipv4_hdr_out; > > > mb->ol_flags |= PKT_TX_IPV4_CSUM; > > > > > > B) User is aware that it is a tunnelled packet and requests HW offload > > > for ipv4_hdr_in and tcp_hdr_in *only*. > > > He doesn't care about outer IP checksum offload. In that case, for FVL > > > he has 2 choices: > > > 1. Treat that packet as a 'proper' tunnelled packet, and fill all the > > > fields: > > > mb->l2_len = udp_hdr_out + vxlan_hdr +eth_hdr_in; > > > mb->l3_len = ipv4_hdr_in; > > > mb->outer_l2_len = eth_hdr_out; > > > mb->outer_l3_len = ipv4_hdr_out; > > > mb->ol_flags |= PKT_TX_UDP_TUNNEL_PKT | PKT_TX_IP_CKSUM | > > > PKT_TX_TCP_CKSUM; > > > > > > 2. As user doesn't care about outer IP hdr checksum, he can treat > > > everything before ipv4_hdr_in as L2 header. > > > So he knows, that it is a tunnelled packet, but makes HW to treat it > > > as ordinary (non-tunnelled) packet: > > > mb->l2_len = eth_hdr_out + ipv4_hdr_out + udp_hdr_out + vxlan_hdr + > > > ehtr_hdr_in; > > > mb->l3_len = ipv4_hdr_in; > > > mb->ol_flags |= PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM; > > > > > > i40e PMD will support both B.1 and B.2, but ixgbe/igb/em PMD supports > > > only B.2. > > > if HW supports both - it will be up to user app which method to choose. > > > tespmd will support both methods, and it should be configurable by user > > > which approach to use (cmdline parameter). > > > So the user can try/test both methods and select an appropriate for him. > > > > > > C) User knows that is a tunnelled packet, and wants HW offload for all 3 > > > checksums: outer IP hdr checksum, inner IP checksum, > inner > > > TCP checksum. > > > Then he has to setup all TX checksum fields: > > > mb->l2_len = udp_hdr_out + vxlan_hdr +eth_hdr_in;; > > > mb->l3_len = ipv4_hdr_in; > > > mb->outer_l2_len = eth_hdr_out; > > > mb->outer_l3_len = ipv4_hdr_out; > > > mb->ol_flags |= PKT_TX_OUT_IP_CKSUM | PKT_TX_UDP_TUNNEL_PKT | > > > PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM; > > > > > > Change notes: > > > v2 changes: > > > remove PKT_TX_IP_CKSUM alias. > > > add PKT_TX_OUT_IP_CKSUM and PKT_TX_OUTER_IPV6 in > > > rte_get_tx_ol_flag_name. > > > spliting mbuf changes into two patches. > > > fix MACLEN caculation issue in i40e driver > > > fix some issues in csumonly.c > > > change cover letter. > > > v3 changes: > > > fix MACLEN caculation issue in i40e driver when non-tunneling packet > > > v4 changes: > > > reorganize patches to avoid compilation to be broken between patches. > > > remove l4_tun_len from mbuf structure. > > > add PKT_TX_OUTER_IPV4 to indicate no IP checksum offload requirement > > > for tunneling packet. > > > change i40e PMD and csum engine due to above changes. > > > > > > v5 changes: > > > according to Konstantin's comments, optimize process_outer_cksums() > > > in order to avoid setting PKT_TX_OUTER_IPV4 flags for > the > > > case when user didn't enable TESTPMD_TX_OFFLOAD_VXLAN_CKSUM > > > > > > Jijiang Liu (3): > > > Redefine PKT_TX_IPV4, PKT_TX_IPV6 and PKT_TX_VLAN_PKT; > > > Replace PKT_TX_VXLAN_CKSUM with PKT_TX_UDP_TUNNEL_PKT, and add 3 TX > > > flags, which are PKT_TX_OUTER_IP_CKSUM, > > > PKT_TX_OUTER_IPV4 and PKT_TX_OUTER_IPV6,and rework csum forward engine > > > and i40e pmd due to these changes; > > > Replace the inner_l2_len and the inner_l3_len field with the > > > outer_l2_len and outer_l3_len field, and rework csum forward > engine > > > and i40e pmd due to these changes; > > > > Acked-by: Konstantin Ananyev <konstantin.ananyev at intel.com> > > Applied with small comments changes suggested by Olivier. > > Thanks everyone for finding a consensus. > It's not easy to accept different of views but we finally did it! > > Lesson learned: every details of an API must be explicited with clear and > short sentences.
>From my side I would like to thank Olivier for all his tremendous help with >that feature. Konstantin > > Thanks > -- > Thomas
