Layout-Agnostic MPI Abstraction for Distributed Computing in Modern C++

Abstract

Message Passing Interface (MPI) has been a well-established technology in the domain of distributed high-performance computing for several decades. However, one of its greatest drawbacks is a rather ancient pure-C interface. It lacks many useful features of modern languages (namely C++), like basic type-checking or support for generic code design. In this paper, we propose a novel abstraction for MPI, which we implemented as an extension of the C++ Noarr library. It follows Noarr paradigms (first-class layout and traversal abstraction) and offers layout-agnostic design of MPI applications. We also implemented a layout-agnostic distributed GEMM kernel as a case study to demonstrate the usability and syntax of the proposed abstraction. We show that the abstraction achieves performance comparable to the state-of-the-art MPI C++ bindings while allowing for a more flexible design of distributed applications.