Hi Olivier, Thanks for looking into this.
> -----Original Message----- > From: Olivier Matz [mailto:olivier.m...@6wind.com] > Sent: Wednesday, January 17, 2018 1:10 AM > To: Xueming(Steven) Li <xuemi...@mellanox.com> > Cc: Thomas Monjalon <tho...@monjalon.net>; Jingjing Wu > <jingjing...@intel.com>; Yongseok Koh <ys...@mellanox.com>; Shahaf Shuler > <shah...@mellanox.com>; dev@dpdk.org > Subject: Re: [PATCH 4/6] ethdev: introduce TX common tunnel offloads > > Hi Xueming, > > On Tue, Jan 09, 2018 at 10:11:08PM +0800, Xueming Li wrote: > > This patch introduce new DEV_TX_OFFLOAD_GENERIC_TNL_CKSUM_TSO flag for > > devices that support tunnel agnostic TX checksum and tso offloading. > > > > Checksum offset and TSO header length are calculated based on mbuf > > inner length l*_len, outer_l*_len and tx offload flags PKT_TX_*, > > tunnel header length is part of inner l2_len, so device HW do cheksum > > and TSO calculation w/o knowledge of perticular tunnel type. > > > > When set application must guarantee that correct header types and > > lengths for each inner and outer headers in mbuf header, no need to > > specify tunnel type. > > > > Signed-off-by: Xueming Li <xuemi...@mellanox.com> > > --- > > lib/librte_ether/rte_ethdev.h | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > > diff --git a/lib/librte_ether/rte_ethdev.h > > b/lib/librte_ether/rte_ethdev.h index 57b61ed41..8457d01be 100644 > > --- a/lib/librte_ether/rte_ethdev.h > > +++ b/lib/librte_ether/rte_ethdev.h > > @@ -1003,6 +1003,15 @@ struct rte_eth_conf { > > * the same mempool and has refcnt = 1. > > */ > > #define DEV_TX_OFFLOAD_SECURITY 0x00020000 > > +/**< Device supports arbitrary tunnel chksum and tso offloading w/o > knowing > > + * tunnel detail. Checksum and TSO are calculated based on mbuf > fields: > > + * l*_len, outer_l*_len > > + * PKT_TX_OUTER_IPV6, PKT_TX_IPV6 > > + * PKT_TX_IP_CKSUM, PKT_TX_TCP_CKSUM, PKT_TX_UDP_CKSUM > > + * When set application must guarantee correct header fields, no need > to > > + * specify tunnel type PKT_TX_TUNNEL_* for HW. > > + */ > > +#define DEV_TX_OFFLOAD_GENERIC_TNL_CKSUM_TSO 0x00040000 > > > > struct rte_pci_device; > > > > I'd like to have more details about this flag and its meaning. > > Let's say we want to do TSO on the following vxlan packet: > Ether / IP1 / UDP / VXLAN / Ether / IP2 / TCP / Data > > With the current API, we need to pass the tunnel type to the hardware with > the flag PKT_TX_TUNNEL_VXLAN. Thanks to that, the driver can forward this > information to the hardware so it knows that the > ip1->length, udp->length and optionally the udp->chksum have to be > updated for each generated segment. > > With your proposal, if I understand properly, it is not expected to pass > the tunnel type in the mbuf. So how can the hardware know if some fields > have to be updated in the outer header? I'm not expert on hardware, the driver has to supply outer and inner L3/L4 offsets, types and which field(s) to fill checksum, no length update as far as I know.
