Interactive Compilation and Performance Analysis with URSA MINOR

This paper proposes solutions to two important problems with parallel programming environments that were not previously addressed. The rst issue is that current compilers are typically black-box tools with which the user has little interaction. Information gathered by the compiler, although potentially very meaningful for the user, is often inaccessible or hard to decipher. Second, compilation and performance analysis tools are not well integrated. While there are many advanced instruments for gathering and browsing performance results of a program, it is di cult to relate this information to the source program, to the applied program transformations, and to the compiler's reasoning. The Ursa Minor tool addresses these issues. The tool is designed to help understand the structure of a program and the information gathered by a compiler in an interactive way. It facilitates the comparison of performance results under di erent environments and the identi cation of potential parallelism, and it provides a repository for this information. Ursa Minor is built using the Polaris compiler infrastructure. We present case studies that show how programmers can use the tool to nd additional parallelism in a compiler-optimized program and to characterize the performance of parallel applications. The tools are currently being used in several projects to develop and study parallel applications and to evaluate parallelizing compilers. These e orts provide feedback for improving the Ursa Minor tool.