Lack of effective performance evaluation and prediction environment is a major barrier to the broader use of high performance computing. Conventional performance environments are based on profiling and event instrumentation. For a system with p processors, there are 2 DSG1 p-p-1 potential parallel sub-task interactions. As parallel systems scale to hundreds of nodes and beyond, the conventional execution profiling approach becomes problematic. Moreover, there are many ways to parallelize an application, and the relative performance of different parallelizations varies with problem size and system ensemble size. The objective of the proposed research is to explore the relevant issues in designing and developing an integrated, concrete, and robust SCALability Analyzer (SCALA) system for performance modeling and prediction of high performance computing programs. DSG1