[mpiwg-rma] RMA WG Telecon

Jim Dinan james.dinan at gmail.com
Wed Sep 12 07:21:52 CDT 2018

In addition to op, hardware acceleration can also be tied to datatype.  For
example, MPI_SUM may be accelerated for integer types, but not floating
point types.  I think it's possible to support such a query using the
recent tools interfaces.  I created a ticket, so we remember to discuss:


On Wed, Sep 12, 2018 at 4:26 AM Joseph Schuchart via mpiwg-rma <
mpiwg-rma at lists.mpi-forum.org> wrote:

> Pavan,
> I listened in for the MPI-RMA WG telco yesterday and found some
> interesting points in it. In particular, I am interested in the
> discussion on atomics and same_op. I support the notion that MPI should
> choose a conservative default to make sure users do not run into
> surprising UB because the implementation expects or supports only
> same_op, which the user may not be aware of.
> As a developer of a framework built on top of MPI RMA I would also be
> interested in getting information from the MPI implementation on which
> atomic operations are actually supported in hardware on the current
> system, which would allow me to pick different implementations of a
> specific feature to fully exploit the available hardware capabilities
> (similar to C++ `std::atomic_is_lock_free`). Are there any plans to
> provide such an interface? This could be used in combination with an
> info key (say `native_op`) that promises that the user will only use a
> mix of operations that are supported in hardware, which would then avoid
> the required fall-back to active messages discussed yesterday.
> Last but not least, I am also interested in the shared memory
> optimization for collectives (iirc, MPI_DISCARD?). I couldn't find an
> issue on Github on this. Is there any publicly available information you
> can share?
> Any input would be much appreciated.
> Many thanks in advance,
> Joseph
> On 09/10/2018 09:21 PM, Balaji, Pavan via mpiwg-rma wrote:
> >
> >
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