A practical approach to performance analysis and modeling of large-scale systems

This tutorial presents a practical approach to the performance modeling of large-scale, scientific applications on high performance systems. The defining characteristic involves the description of a proven modeling approach, developed at Los Alamos, of full-blown scientific codes, ranging from a few thousand to over 100,000 lines, that has been validated on systems containing 1,000's of processors. We show how models are constructed and demonstrate how they are used to predict, explain, diagnose, and engineer application performance in existing or future codes and/or systems. Our approach does not require specific tools but rather is applicable across commonly used environments. Moreover, since our performance models are parametric, they imbue the user with the ability to "experiment ahead" with different system configurations or algorithms/coding strategies. Both will be demonstrated in studies emphasizing the application of these modeling techniques including: verifying system performance, comparison of large-scale systems, and examination of possible future systems.