FWIW: I’ve started getting some of these queries myself - it is indeed confusing. To make things worse, uGNI and shared memory will also be in libfabric as well, so we’ll basically have every network available three (or more!) different ways
> On Oct 12, 2015, at 8:47 AM, Jeff Squyres (jsquyres) <jsquy...@cisco.com> > wrote: > > Rolf: can you add this to the agenda? > > We're now adding multiple ways to get to the same underlying network > transport, and it's getting confusing for users (I've fielded several > off-list questions from users about this issue). > > - MXM: can be accessed via Yalla, the MXM MTL, (soon) UCX, and (soon) > libfabric > - PSM: can be accessed via the PSM MTL and libfabric > - verbs: can be accessed via the openib BTL and libfabric > - PSM2: ditto > - uGNI: can be accessed via the uGNI BTL, portals(4?), and (soon) UCX > - shared memory: can be accessed via sm, vader, and (soon) UCX > > But you can also look at this from a different perspective: > > - IB: can be used via Yalla, MXM MTL, UCX, libfabric (multiple ways) > - RoCE: can be used via ^^some (or all? I'm not sure) of these > - Cray: can be used via the uGNI BTL, portals(4?), and (soon) UCX > > ...what's a user supposed to use? > > And more specifically, how can a user enable or disable a specific type of > network? Or API? > > A recent (off list) example I had was a user who was frustrated trying to > figure out how to disable all forms of MXM (note: this is a larger issue than > just MXM). > > Bottom line: underlying networks can be accessed through multiple upper-layer > APIs, and it creates both a mapping problem for the MPI implementation, and a > usability issue for users trying to be specific about which network(s) they > want the MPI implementation to use. > > I don't have a solution (or even a proposal) here. This is something we need > to think / talk about. > > -- > Jeff Squyres > jsquy...@cisco.com > For corporate legal information go to: > http://www.cisco.com/web/about/doing_business/legal/cri/ > > _______________________________________________ > devel mailing list > de...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/devel > Link to this post: > http://www.open-mpi.org/community/lists/devel/2015/10/18154.php
