Hi Mark,

quoted

quoted

quoted

+
+void
+gso_parse_packet(struct rte_mbuf *pkt)

There is a function rte_net_get_ptype() that supposed to provide similar

functionality.

quoted

So we probably don't need to create a new SW parse function here, instead

would be better

quoted

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