Re: [PATCH RFC 0/9] A rendezvous module

[Jason Gunthorpe <jgg@nvidia.com>]

On Fri, Mar 19, 2021 at 09:58:21PM +0000, Wan, Kaike wrote:

> > On 3/19/2021 4:59 PM, Wan, Kaike wrote:
> > >> From: Jason Gunthorpe <jgg@nvidia.com>
> > >> Sent: Friday, March 19, 2021 4:55 PM
> > >> To: Rimmer, Todd <todd.rimmer@intel.com>
> > >> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>;
> > >> Wan, Oh, there is lots of stuff in UCX, I'm not surprised you
> > >> similarities to what PSM did since psm/libfabric/ucx are all solving the
> > same problems.
> > >>
> > >>>> rv seems to completely destroy alot of the HPC performance offloads
> > >>>> that vendors are layering on RC QPs
> > >>
> > >>> Different vendors have different approaches to performance and chose
> > >>> different design trade-offs.
> > >>
> > >> That isn't my point, by limiting the usability you also restrict the
> > >> drivers where this would meaningfully be useful.
> > >>
> > >> So far we now know that it is not useful for mlx5 or hfi1, that
> > >> leaves only hns unknown and still in the HPC arena.
> > > [Wan, Kaike] Incorrect. The rv module works with hfi1.
> > 
> > Interesting. I was thinking the opposite. So what's the benefit? When would
> > someone want to do that?

> [Wan, Kaike] This is only because rv works with the generic Verbs
> interface and hfi1 happens to be one of the devices that implements
> the Verbs interface.

Well, it works with everything (except EFA), but that is not my point.

I said it is not useful.

Jason