ICAP: Designing Inrush Current Aware Power Gating Switch for GPGPU

The leakage energy of GPGPU can be reduced by power gating the idle logic or undervolting the storage structures; however, the performance and reliability of the system degrades due to large wake up time and inrush current at time of activation. In this paper, we thoroughly analyze the realistic Break-Even Time (BET) and inrush current for various components in GPGPU architecture considering the recent design of multi-modal Power Gating Switch (PGS). Then, we introduce a new PGS which covers the current PGS drawbacks. Our redesigned PGS is carefully tailored to minimize the inrush current and BET. GPGPU-Sim simulation results for various applications, show that, with incorporating the proposed PGS into GPGPU-Sim, we can save leakage energy up to 82%, 38%, and 60% for register files, integer units, and floating units respectively.