Re: [PATCH v2] RDMA/CMA: fix iWARP adapter TCP port space usage

Jason Gunthorpe
2010-06-12T01:56:52Z

On Fri, Jun 11, 2010 at 08:18:43PM -0500, Steve Wise wrote:

> Further, its not even needed for IB, just iWARP. That's an unnecessary
> admin pain IMO.

IB already completely seperates from the host stack, that is why it
isn't effected by this problem. It has both a seperate port numbering
space (in rdma cm) and a separate addressing space (GID).

The entire problem with iWARP is that it is trying to not be
seperate, unlike IB. So.. simple answer: use a seperate IP, or use a
seperate port space (ie don't use the TCP protocol number).

ROCEE won't have this problem either..

> iWARP should and can easily co-exist with the host TCP by sharing
> the port space. But, as Roland stated already, maybe the only way
> forward it to get end-user pressure applied at the appropriate
> places! :)

*shrug* This isn't going to happen until netdev decides to design-in
statefull offload. I doubt that is going to happen any time
soon. I've already seen Linux max out 40GE on benchmarks, so it is
hard to see what the driver would be.

Jason