FastLanes: An FPGA accelerated GPU microarchitecture simulator

Abstract

Graphic Processing Units (GPUs) have emerged as a new general purpose computing platform that attracts significant research efforts. Currently, GPU architecture research resorts to time-consuming software simulations to evaluate microarchitecture innovations. In this paper, we propose FastLanes, an FPGA based simulator for a generic GPU microarchitecture, to enable hardware-accelerated simulation. FastLanes consists of a function model and a timing model, both implemented on FPGA. The functional model implements the full functionality of a multiprocessor of GPU and emulates multiple multiprocessors via time-division multiplexing. We develop a hybrid implementation strategy in which certain GPU logic is directly mapped to FPGA while the other logic is simulated by reusing the same FPGA logic. A corresponding context shifting mechanism is proposed to store execution states of threads from FPGA to external on-board memory, and vice versa. Such a mechanism makes it possible to simulate hundreds of GPU cores on a single FPGA evaluation board. Driven by the functional simulation results, the timing model considers the detailed configuration of GPU microarchitecture to derive the performance evaluation. A compiler tool-chain is also developed to allow the execution of NVIDIA GPU binary on FastLanes. Experimental results prove that FastLanes outperforms its software equivalent by up to 2 orders of magnitude.