WHAT: Open our low-level communication infrastructure by moving all
necessary components
(btl/rcache/allocator/mpool) down in OPAL
WHY: All the components required for inter-process communications are
currently deeply integrated in the OMPI
layer. Several groups/institutions have express interest
in having a more generic communication
infrastructure, without all the OMPI layer dependencies.
This communication layer should be made
available at a different software level, available to
all layers in the Open MPI software stack. As an
example, our ORTE layer could replace the current OOB
and instead use the BTL directly, gaining
access to more reactive network interfaces than TCP.
Similarly, external software libraries could take
advantage of our highly optimized AM (active message)
communication layer for their own purpose.
UTK with support from Sandia, developped a version of
Open MPI where the entire communication
infrastucture has been moved down to OPAL
(btl/rcache/allocator/mpool). Most of the moved
components have been updated to match the new schema,
with few exceptions (mainly BTLs
where I have no way of compiling/testing them). Thus,
the completion of this RFC is tied to
being able to completing this move for all BTLs. For
this we need help from the rest of the Open MPI
community, especially those supporting some of the BTLs.
A non-exhaustive list of BTLs that
qualify here is: mx, portals4, scif, udapl, ugni, usnic.
WHERE: bitbucket.org/bosilca/ompi-btl (updated today with respect to
trunk r31952)
TIMEOUT: After all the BTLs have been amended to match the new
location and usage. We will discuss
the last bits regarding this RFC at the Open MPI
developers meeting in Chicago, June 24-26. The
RFC will become final only after the meeting.
