Re: [PATCH net-next 02/11] ethtool: Add loopback netlink UAPI definitions

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Hi Andrew,

>> One more issue is the test data generator location. The data generator
>> is not always the CPU. We have HW generators located in components like
>> PHYs or we may use external source (remote loopback).
> 
> At the moment, we don't have a Linux model for such generators. There
> is interest in them, but nobody has actually stepped up and proposed
> anything. I do see there is an intersect, we need to be able to
> represent them in the topology, and know which way they are pointing,
> but i don't think they have a direct influence on loopback.

If I'm following Oleksij, the idea would be to have on one side the
ability to "dump" the link topology with a finer granularity so that we
can see all the different blocks (pcs, pma, pmd, etc.), how they are
chained together and who's driving them (MAC, PHY (+ phy_index), module,
etc.), and on another side commands to configure loopback on them, with
the ability to also configure traffic generators in the future, gather
stats, etc.

Another can of worms for sure, and probably too much for what Björn is
trying to achieve. It's hard to say if this is overkill or not, there's
interest in that for sure, but also quite a lot of work to do...

Maxime