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

[Thomas Monjalon <thomas@monjalon.net>]

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?