Re: [RFC PATCH 00/13] Ultra Ethernet driver introduction

Nikolay Aleksandrov
2025-03-12T09:40:08Z

On 3/8/25 8:46 PM, Leon Romanovsky wrote:
> On Fri, Mar 07, 2025 at 01:01:50AM +0200, Nikolay Aleksandrov wrote:
>> Hi all,
>
> <...>
>
>> Ultra Ethernet is a new RDMA transport.
> > Awesome, and now please explain why new subsystem is needed when
> drivers/infiniband already supports at least 5 different RDMA
> transports (OmniPath, iWARP, Infiniband, RoCE v1 and RoCE v2).
>

As Bernard commented, we're not trying to add a new subsystem, but
start a discussion on where UEC should live because it has multiple
objects and semantics that don't map well to the current
infrastructure. For example from this set - managing contexts, jobs and
fabric endpoints. Also we have the ephemeral PDC connections
that come and go as needed. There more such objects coming with more
state, configuration and lifecycle management. That is why we added a
separate netlink family to cleanly manage them without trying to fit
a square peg in a round hole so to speak. In the next version I'll make
sure to expand much more on this topic. By the way I believe Sean is
working on the verbs mapping for parts of UEC, he can probably also
share more details.
We definitely want to re-use as much as possible from the current
infrastructure, noone is trying to reinvent the wheel.

> Maybe after this discussion it will be very clear that new subsystem
> is needed, but at least it needs to be stated clearly.
>
> An please CC RDMA maintainers to any Ultra Ethernet related discussions
> as it is more RDMA than Ethernet.
>

Of course it's RDMA, that's stated in the first few sentences, I made a
mistake with the "To", but I did add linux-rdma@ to the recipient list.
I'll make sure to also add the rdma maintainers personally for the next
version and change the "to".

> Thanks

Cheers,
Nik