From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH 1/2] rdma/cm: support option to allow manually setting IB path Date: Mon, 5 Oct 2009 12:15:25 -0600 Message-ID: <20091005181525.GL5191@obsidianresearch.com> References: <20091005175656.GK5191@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sean Hefty Cc: linux-rdma , Roland Dreier List-Id: linux-rdma@vger.kernel.org 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 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html