What RDMA Means to MPI Apps

Jeff Squyres writes that Remote Direct Memory Access (RDMA) is basically a common implementation of a more general concept: RMA (remote memory access), or directly reading and writing to a peer’s memory space:

In general, RMA is a pretty lousy match for MPI’s message-based semantics. Mapping the abstractions provided by RMA concepts to those of two-sided message passing is a complicated process. Indeed, many of the one-sided RMA benefits can be lost when applying them to two-sided communications.

Read the Full Story or check out this presentation from Paul Grun (System Fabrics Works) presenting Dense Clusters Based On RoCE (RDMA over Converged Ethernet).

httpv://www.youtube.com/watch?v=2bn0eDOzReg

Recorded at the 2011 OpenFabrics International Workshop.