> -----Original Message----- > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Ananyev, Konstantin > Sent: Wednesday, August 30, 2017 10:39 AM > To: Kavanagh, Mark B <mark.b.kavan...@intel.com>; Hu, Jiayu > <jiayu...@intel.com> > Cc: dev@dpdk.org; Tan, Jianfeng <jianfeng....@intel.com> > Subject: Re: [dpdk-dev] [PATCH 2/5] gso/lib: add TCP/IPv4 GSO support > > Hi Mark, > > > >> > + > > >> > +void > > >> > +gso_parse_packet(struct rte_mbuf *pkt) > > >> > > >> There is a function rte_net_get_ptype() that supposed to provide similar > > >functionality. > > >> So we probably don't need to create a new SW parse function here, instead > > >would be better > > >> to reuse (and update if needed) an existing one. > > >> Again user already might have l2/l3/l4.../_len and packet_type setuped. > > >> So better to keep SW packet parsing out of scope of that library. > > > > > >Hmm, I know we have discussed this design choice in the GRO library, and I > > >also think it's > > >better to reuse these values. > > > > > >But from the perspective of OVS, it may add extra overhead, since OVS > > >doesn't > > >parse every > > >packet originally. Maybe @Mark can give us more inputs from the view of > > >OVS. > > > > Hi Jiayu, Konstantin > > > > For GSO, the application needs to know: > > - the packet type (as it only currently supports TCP/IPv4, VxLAN, GRE > > packets) > > - the l2/3/4_lens, etc. (in order to replicate the original packet's > > headers across outgoing segments) > > > > For this, we can use the rte_net_get_ptype function, as per Konstantin's > > suggestion, as it provides both - thanks Konstantin! > > > > WRT the extra overhead in OvS: TSO is the defacto standard, and GSO is > > provided purely as a fallback option. As such, and since the > > additional packet parsing is a necessity in order to facilitate GSO, the > > additional overhead is IMO acceptable. > > As I remember, for TSO in DPDK user still have to provide l2/l3/l4_len and > mss information to the PMD. > So unless user knows these value straightway (user creates a packet himself) > some packet processing will be unavailable anyway. > Konstantin
s/unavailable/unavoidable/ sorry for bad typing. Konstantin > > > > Thanks, > > Mark > >
