Re: [dpdk-dev] [PATCH 2/2] doc: announce new mbuf field for LRO

[Matan Azrad <matan@mellanox.com>]

Hi

From: Thomas Monjalon
> 10/08/2019 23:31, Thomas Monjalon:
> > 06/08/2019 20:17, Andrew Rybchenko:
> > > On 8/6/19 5:56 PM, Matan Azrad wrote:
> > > > The API breakage is because the ``tso_segsz`` field was documented
> > > > for LRO.
> > > >
> > > > The ``tso_segsz`` field in mbuf indicates the size of each segment
> > > > in the LRO packet in Rx path and should be provided by the LRO
> > > > packet port.
> > > >
> > > > While the generic LRO packet may aggregate different segments
> > > > sizes in one packet, it is impossible to expose this information
> > > > for each segment by one field and it doesn't make sense to expose
> > > > all the segments sizes in the mbuf.
> > > >
> > > > A new field may be added as union with the above field to expose
> > > > the number of segments aggregated in the LRO packet.
> > > >
> > > > Signed-off-by: Matan Azrad <matan@mellanox.com>
> > > > ---
> > > > --- a/doc/guides/rel_notes/deprecation.rst
> > > > +++ b/doc/guides/rel_notes/deprecation.rst
> > > > +* mbuf: Remove ``tso_segsz`` mbuf field providing for LRO
> > > > +support. Use union
> > > > +  block for the field memory to be shared with a new field
> > > > +``lro_segs_n``
> > > > +  indicates the number of segments aggregated in the LRO packet.
> > >
> > > I think that the number of segments is more logical in the case of LRO.
> > > The question (already asked by Konstantin) is why it is needed at
> > > all (statistics?). If so, it still makes sense.
> > >
> > > Segment size is misleading here, since not all segments could be the
> > > same size. So,
> > >
> > > Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
> > >
> > > As far as I can see bnxt and qede do not fill it in.
> > > mlx5 and vmxnet3 have the number of segments (vmxnet3 has segment
> > > size sometimes and sometimes use a function to guess the value).
> > > So both will win from the change.
> > > It looks like virtio does not have number of segments. CC Maxime to
> > > comment.
> >
> > I support improving the API for LRO.
> > Unfortunately, the consensus is not strong enough at the moment.
> 
> We had no progress about LRO field in mbuf.
> Is it a change we would like to have in 20.11?
> 
+1 to make the change.