Re: [dpdk-dev] [PATCH 0/3] refresh NIC features matrix

[Ajit Khaparde <ajit.khaparde@broadcom.com>]

On Fri, Apr 17, 2020 at 9:32 AM Thomas Monjalon <thomas@monjalon.net> wrote:

> Call for action below (especially for octeontx2 and virtio):
>
> 24/03/2020 09:36, Andrew Rybchenko:
> > On 3/20/20 2:15 PM, Zhang, Qi Z wrote:
> > > From: Thomas Monjalon <thomas@monjalon.net>
> > >> 20/03/2020 06:35, Zhang, Qi Z:
> > >>> From: Thomas Monjalon <thomas@monjalon.net>
> > >>>>
> > >>>> This series aims to clean-up the big table of ethdev features:
> > >>>>   http://doc.dpdk.org/guides/nics/overview.html#id1
> > >>>>
> > >>>> We could reorganize the information in this table, maybe split it or
> > >>>> add/remove some rows.
> > >>>> Before going to such reorganization, we should clean it up.
> [...]
> > >>>> More columns can be removed by merging PF/VF and vector datapaths.
> > >>>> If a feature cannot be supported in all cases, it should be marked
> > >>>> as partially supported (P).
>
> I see that Intel merged "vec" columns for its PMDs.
> We are still missing octeontx2 and virtio.
> In order to make sure the message is received,
> I suggest blocking any patch in these PMDs until features matrix is fixed.
>
>
> > >>>> If a feature is PF-specific (like flow control), that's OK to mark
> > >>>> it fully supported because it's obviously impossible for VF.
> > >>>> There are also some features which were probably marked in some
> > >>>> columns and missed in its VF or vector counterpart.
>
> Ideally we should remove all these columns (VF to be discussed):
>
> > >>>>   - cxgbevf
> > >>>>   - fm10k_vf
> > >>>>   - hns3_vf
> > >>>>   - i40e_vf
> > >>>>   - igb_vf
> > >>>>   - ixgbe_vf
> > >>>>   - octeontx2_vec
> > >>>>   - octeontx2_vf
> > >>>>   - qede_vf
> > >>>>   - virtio_vec
> > >>>>
> > >>>> The total gain is to reduce the table size from 71 to 47 columns.
> > >>>
> > >>> I agree to remove all the column with "vec", since vector PMD can be
> > >>> regarded as a feature of the a PMD.
> > >>> But I'm not sure if it is a good idea to merge VF and PF into one
> column.
> > >>> From my view, for intel device, VF driver and PF driver just share
> the code,
> > >>> but they actually are running at two different context.
> > >>> And likely they will support different feature, merge into one
> column may
> > >>> confuse our customer if they want to understand what exactly the PMD
> > >>> support.
> > >>
> > >> I understand you have 2 different datapaths.
> > >> My arguments are:
> > >>    - it is the same NIC
> > >
> > > Yes, but one device can be polymorphic, ideally i40e and i40evf
> > > could be in two different folder, and the common part can be a
> > > library in driver/common/i40e.
> [...]
> >
> > >>    - you cannot summarize everything in a table
> > >>    - we have two many columns to make it readable
> > >
> > > I don't think columns number is critical, typically user just need
> > > to focus on the first column and the specific driver's column,
> >
> > Too many columns still makes it harder to read/analyze. I think
> > the main goal of the table is too help making NIC choice to
> > be installed in a server and you can't make a choice between
> > PF and VF. Difference between PF and VF capabilities is
> > a separate story and out-of-scope of the table.
> > We have a new driver(s) in each DPDK release and table is
> > already big and will grow more and more.
> >
> > > I guess it may not a big challenge to enable some filter by front end
> web technique?
>
+1


> > >
> > >> I think the right solution is mark features as partially available
> (P), and give
> > >> details in the driver guide documentation.
>
> Other opinions about removing/merging VF columns?
>
PF and VF devices can have different feature support.
It will be good to keep them separate.
If it is difficult to tabulate the capabilities for various devices
in a single page, then marking it with (P) is fine.
The Driver guide should carry the differences between PF and VF
capabilities anyway.