Design and Implementation of MPI on Portals 3.0

This paper describes an implementation of the Message Passing Interface (MPI) on the Portals 3.0 data movement layer. Portals 3.0 provides low-level building blocks that are flexible enough to support higher-level message passing layers such as MPI very efficiently. Portals 3.0 is also designed to allow for programmable network interface cards to offload message processing from the host processor. We will describe the basic building blocks in Portals 3.0, show how they can be put together to implement MPI, and describe the protcols of an MPI implementation. We will look at several key operations within an MPI implementation and describe the effects that a Portals 3.0 implementation has on scalability and performance.