JIT-assisted fast-forward embedding and instrumentation to enable fast, accurate, and agile simulation

Computer architects need fast and accurate simulation to research new computing systems, but architects are also increasingly demanding agile simulation to give them flexibility to productively explore the interaction between software and hardware. In this paper, we propose JIT-assisted fast-forward embedding (JIT-FFE) and JIT-assisted fast-forward instrumentation (JIT-FFI) for fast, accurate, and agile simulation. JIT-FFE enables zero-copy architectural state transfer between a state-of-the-art dynamic-binary-translation-based instruction-set simulator and a detailed microarchitectural simulator. JIT-FFI enables productive implementation of fast functional profiling and warmup. We have implemented these two techniques in a new tool, called PydginFF, which can be integrated with any C/C++ detailed simulator. We evaluate PydginFF within the context of the gem5 detailed simulator for both periodic sampling (SMARTS) and targeted sampling (SimPoint) and demonstrate that PydginFF reduces simulation time of fast-forward-based sampling by over 10×.