Swift/T: Large-scale application composition via distributed-memory dataflow processing

Many scientific applications are conceptually built up from independent component tasks as a parameter study, optimization, or other search. Large batches of these tasks may be executed on high-end computing systems; however, the coordination of the independent processes, their data, and their data dependencies is a significant scalability challenge. Many problems must be addressed, including load balancing, data distribution, notifications, concurrent programming, and linking to existing codes. In this work, we present Swift/T, a programming language and runtime that enables the rapid development of highly concurrent, task-parallel applications. Swift/T is composed of several enabling technologies to address scalability challenges, offers a high-level optimizing compiler for user programming and debugging, and provides tools for binding user code in C/C++/Fortran into a logical script. In this work, we describe the Swift/T solution and present scaling results from the IBM Blue Gene/P and Blue Gene/Q.