Re: [dpdk-dev] [PATCH v5 0/5] ethdev: introduce configurable flexible item

[Slava Ovsiienko <viacheslavo@nvidia.com>]

Hi, Ferruh

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit@intel.com>
> Sent: Thursday, October 14, 2021 19:09
> To: Slava Ovsiienko <viacheslavo@nvidia.com>; dev@dpdk.org
> Cc: Raslan Darawsheh <rasland@nvidia.com>; Matan Azrad
> <matan@nvidia.com>; Shahaf Shuler <shahafs@nvidia.com>; Ori Kam
> <orika@nvidia.com>; Gregory Etelson <getelson@nvidia.com>; NBU-Contact-
> Thomas Monjalon <thomas@monjalon.net>; Qi Zhang <qi.z.zhang@intel.com>
> Subject: Re: [dpdk-dev] [PATCH v5 0/5] ethdev: introduce configurable
> flexible item
> 
> On 10/12/2021 1:54 PM, Viacheslav Ovsiienko wrote:
> > 1. Introduction and Retrospective
> >

.. snip ..

> > Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
> >
> > Gregory Etelson (4):
> >    ethdev: support flow elements with variable length
> >    ethdev: implement RTE flex item API
> >    app/testpmd: add jansson library
> >    app/testpmd: add flex item CLI commands
> >
> > Viacheslav Ovsiienko (1):
> >    ethdev: introduce configurable flexible item
> >
> 
> Hi Viacheslav,
> 
> This as a nice feature, thanks. But my concern/question is how to test it?
> 
> I think testing requires HW that support custom (flexible) protocol, and I
> assume mellanox devices supports it, does it mean specific HW is required to
> test the feature?

Hypothetically,  the feature can be implemented in software (as well as the
entire RTE flow engine) , but you are right - the hardware in needed - 
Mellanox NICs provide support for Flex Item feature since ConnectX-6DX.
It seems mlx5 is going to be only the PMD supporting the Flex Item
at in hardware for the moment. We tried to avoid any vendor specifics in this API,
and I hope we succeeded with making it commoditized.
> 
> Or can we use flexible item to emulate an existing protocol and test it on any
> hardware?
Mmm, let me think a bit.
If we have some NIC supporting, say, UDP, and we would like to handle
UDP with Flex Item (for testing purposes only) - we should update NIC PMD
accordingly - it should handle Flex Item API and recognize Flex Item in Flows.
So, it is rather the question about updating other PMDs and we did not think
in that direction. But it is feasible, I guess.

> If so what do you think about adding more documentation to
> describe how this can be done?

We are going to add couple of examples of Flex Item API usage (closer to rc3)
The Flex Item idea is simple, but there are a lot of parameters and structures, so
good examples must be provided in documentation. These ones
will be focused mostly on Flex Item API and can be used as guides for PMD
potential testing implementations.

With best regards,
Slava