This prospectus describes research in the field of software engineering to simplify programming of parallel computers. It focuses specifically on performance diagnosis, the process of finding and explaining sources of inefficiency in parallel programs. Considerable research already has been done to simplify perf onnance diagnosis. but with mixed success. Two elements are missing from existing research:

1. There is no general theory of how expert programmers do performance diagnosis. As a result, it is difficult for researchers to compare existing work or fit their work to programmers. It is difficult for programmers to locate products of existing research that meet their needs.
2. There is no automated, adaptable software to help programmers do performance diagnosis. Existing software is either automated but limited to very specific circumstances, or is general but not is automated for most tasks.

The research described here addresses both of these issues. The research will develop and validate a theory of performance diagnosis. based on general models on diagnostic problem-solving. It will design and evaluate a computer program (called Poirot) that employs the theory to automatically, adaptably support perfonnance diagnosis.