Swift-Sim: A Modular and Hybrid GPU Architecture Simulation Framework

Simulation tools are critical for architects to quickly estimate the impact of aggressive new features of GPU architecture. Existing cycle-accurate GPU simulators are typically cumbersome and slow to run. We observe that it is time-consuming and unnecessary for cycle-accurate GPU simulators to perform detailed simulations for the entire GPU when exploring the design space of specific components. This paper proposes Swift-Sim, a modular and hybrid GPU simulation framework. With a highly modular design, our framework can choose appropriate modeling approaches for each component according to requirements. For components of interest to architects, we use cycle-accurate simulation to evaluate new GPU architectures. For other components, we use analytical modeling, which accelerates simulation speed with only minor and acceptable degradation in overall accuracy. Based on this simulation framework, we present two working examples of hybrid modeling that simulate the ALU pipeline and memory accesses using analytical models. We further implement two GPU performance simulators with different levels of simplification based on Swift-Sim and evaluate them using configurations from real GPUs. The results show that the two simulators achieve an 82.6x and 211.2x geometric mean speedup compared to Accel-Sim with insignificant accuracy degradation,