high performance computing on graphics processing units: hgpu.org

Directive-based programming models provide high-level of abstraction thus hiding complex low-level details of the underlying hardware from the programmer. One such model is OpenACC that is also a portable programming model allowing programmers to write applications that offload portions of work from a host CPU to an attached accelerator (GPU or a similar device). The model is gaining popularity and being used for accelerating many types of applications, ranging from molecular dynamics codes to particle physics models. It is critical to evaluate the correctness of the OpenACC implementations and determine its conformance to the specification. In this paper, we present a robust and scalable testing infrastructure that serves this purpose. We worked very closely with three main vendors that offer compiler support for OpenACC and assisted them in identifying and resolving compiler bugs helping them improve the quality of their compilers. The testsuite also aims to identify and resolve ambiguities within the OpenACC specification. This testsuite has been integrated into the harness infrastructure of the TITAN machine at Oak Ridge National Lab and is being used for production. The testsuite consists of test cases for all the directives and clauses of OpenACC, both for C and Fortran languages. The testsuite discussed in this paper focuses on the OpenACC 1.0 feature set. The framework of the testsuite is robust enough to create test cases for 2.0 and future releases. This work is in progress.