Extending Sniper with Support to Access Operand Values: A Case Study on Reusability Measurement

This work presents the augmentation of Sniper, a state-of-the-art multi/many-core simulator, with access to the operand values of a specific group of instructions. Our motivation for accessing the operand values is given because computer programs, in particular graphic and multimedia applications, are characterized by a high degree of redundancy which can be exploited by dynamic instruction reuse techniques. This paper falls into the category of "open architectures" starting from the open-source concept, as it provides researchers with a methodology for reading the values of instruction operands. The most important added value is a technical one, comprising details about the simulator’s architecture and our modifications. Furthermore, we propose a simulation methodology to study the potential reusability of specific types of dynamic instructions. The experimental study is done on the SPLASH-II benchmark suite under different parameters using the modified simulator. Among parameters we vary the number of cores, the compiler optimization method and the operand history length (depth of different operand values stored for each instruction). Our results are indicating a promising potential of reusability, on average varying from 84% to 87%, on selected types of dynamic instructions and lead to the idea of implementing a 4-way associative reuse buffer in a multi/many-core system. The level of optimization of the compiler influences the degree of reusability and overall performance. A rough estimation of potential gain in performance (speedup) is also calculated, reaching a maximum of 17.5% and 3.6% on average.