To improve performance of large-scale scientific applications, scientists or tuning experts make various empirical attempts to change compiler options, program parameters or even the syntactic structure of programs. Those attempts followed by performance evaluation are repeated until satisfactory results are obtained. On account of combinatorial explosion of possible attempts, the task of performance tuning requires a great deal of time and effort, and hence scientists/tuning experts have a tendency to make decisions on what to be explored just based on their intuition or good sense of tuning. 続きを読む →