MPI Runtime Error Detection with MUST: Advanced Error Reports

The Message Passing Interface (MPI) is a widely used paradigm for distributed memory programming. Its API is primarily designed for good performance and less for usability; it provides only very limited abstractions that help enforce its correct use. As a result, application developers need tools that aid in the detection and removal of MPI usage errors. Our runtime error detection tool MUST addresses this issue and provides a wide range of automatic correctness checks. MUST uses state-of-the-art approaches to cope with complex MPI semantics like derived datatypes, collective operations, and wildcard receive operations. However, equally important to detecting correctness violations, is that such correctness tools present all details of the violating MPI call(s) required to pinpoint the problem in the source code and to remove the error. In this paper we focus on the error reports presented by MUST and propose a new set of error reports that present complex errors with fine-grained details of the error situation. This includes a deadlock view and a view for usage errors in complex MPI datatypes.