Extending MUST to Check Hybrid-Parallel Programs for Correctness Using the OpenMP Tools Interface

Abstract

Current High Performance Computing (HPC) systems consist of compute nodes that can communicate via an interconnect. Each compute node features mul-tiple compute cores that can access shared-memory. The Message Passing Interface (MPI) is the de-facto standard for the programming of distributed memory applica-tions. At the same time, OpenMP is a well-suited parallel programming paradigm to utilize the parallel cores within a compute node. Thus, current HPC systems encour-age a hybrid programming approach that combines MPI with OpenMP. However, using both programming paradigms at the same time can lead to more error-prone applications. The runtime correctness checking tool MUST supports programmers in the detection and removal of MPI-specific programming defects. We present an extension of MUST towards the analysis of OpenMP-MPI parallel applications in order to support programmers that combine both paradigms. This includes thread-safety concerns in MUST itself, an extended event model based on the upcoming OpenMP Tools Interface (OMPT), as well as a prototypical error analysis with a synthetic example. We further discuss classes of defects that are specific to OpenMP applications and highlight techniques for their detection.