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 > > Thanks, > Mark >
