Supporting Enhanced Exception Handling with OpenMP in Object-Oriented Languages

Abstract

The proliferation of parallel processing in shared-memory applications has encouraged developing assistant frameworks such as OpenMP. OpenMP has become increasingly prevalent due to the simplicity it offers to elegantly and incrementally introduce parallelism. However, it still lacks some high-level language features that are essential in object-oriented programming. One such mechanism is that of exception handling. In languages such as Java, the concept of exception handling has been an integral aspect to the language since the first release. For OpenMP to be truly embraced within this object-oriented community, essential object-oriented concepts such as exception handling need to be given some attention. The official OpenMP standard has little specification on error recovery, as the challenges of supporting exception-based error recovery in OpenMP extends to both the semantic specifications and related runtime support. This paper proposes a systematic mechanism for exception handling with the co-use of OpenMP directives, which is based on a Java implementation of OpenMP. The concept of exception handling with OpenMP directives has been formalized and categorized. Hand in hand with this exception handling proposal, a flexible approach to thread cancellation is also proposed (as an extension on OpenMP directives) that supports this exception handling within parallel execution. The runtime support and its implementation are discussed. The evaluation shows that while there is no prominent overhead introduced, the new approach provides a more elegant coding style which increases the parallel development efficiency and software robustness.