[ofa-general] RE: tcp/rdma port unification patch in librdmacm

[Steve Wise]

Or Gerlitz wrote:
> Steve Wise wrote:
>> Or maybe map PS_TCP port space to the be the unified space, and have 
>> a new PS_RDMA or PS_IB port space that doesn't? At and second 
> Please note that the rdma-cm derives the IB Service-ID from the port 
> space and the port provided to rdma_resolve_addr - and this is done 
> along the lines of the IBTA "RDMA IP CM Service" annex A11.
> So we would need to have PS_IB_UD and PS_IB_RC that SID(ps=TCP, 
> port=X) = SID(ps=IB_RC, port=X)
> at first thought this is possible and would add too much compatibility 
> issues - except for the need to provide an app with the means to sense 
> if the underlying librdmacm support the _IB port spaces.
>
> Still, I would like to avoid the case where someone runs MPI job over 
> RDMA-CM over IB and librdmacm opens/bounds to all these sockets - so 
> the preferred solution - for my taste would be some setting done by 
> the user to have librdmacm allocate socket / carve a port - and it 
> wouldn't be the default. For example, using an environment variable, 
> e.g similar to the libibverbs fork support.
>

I could live with that.  It would allow taking advantage of this 
functionality without changing all the apps.