Re: [PATCH 1/2] rdma/cm: support option to allow manually setting IB path

Jason Gunthorpe
2009-10-05T18:15:25Z

On Mon, Oct 05, 2009 at 11:08:51AM -0700, Sean Hefty wrote:
> >On Mon, Oct 05, 2009 at 10:43:44AM -0700, Sean Hefty wrote:
> >> Export rdma_set_ib_paths to user space to allow applications to
> >> manually set the IB path used for connections. This allows
> >> alternative ways for a user space application or library to obtain
> >> path record information, including retrieving path information
> >> from cached data, avoiding direct interaction with the IB SA.
> >> The IB SA is a single, centralized entity that can limit scaling
> >> on large clusters running MPI applications.
> >
> >Um, isn't this kind of low level control exactly why we have the IB
> >CM?
>
> There are very few apps that I'm aware of (one to be precise) that have coded
> directly to the libibcm.

I've done several..

But that isn't really the point, IB CM already provides this API so,
why corrupt the RDMA CM abstraction with this?

Jason