Adaptively tolerate power-gating-induced power/ground noise under process variations

Power gating is one of the most effective techniques to reduce the leakage power in multiprocessor system-on-chips (MPSoCs). However, the power-mode transition during the power gating period of an individual processing unit will introduce serious power/ground (P/G) noise to the neighboring processing units. As technology scales, the P/G noise problem becomes a severe reliability threat to MPSoCs. At the same time, the increasing manufacturing process variations also bring uncertainties to the P/G noise problem and make it difficult to predict and deal with. In order to address this problem, for the first time, this paper analyzes the power-gating-induced P/G noise in the presence of process variations, and proposes a hardware-software collaborated online method to adaptively protect processing units from P/G noise. Sensor network-on-chip (SENoC) is used to gather noise information and coordinate different system components. Meanwhile an online software-based algorithm is developed to effectively decide the noise impact range and arrange protections for affected processing units based on the collected information. We evaluate the proposed method through Monte Carlo simulations on a NoC-based MPSoC platform. The experimental results show that for a set of real applications, our method achieves on average 13.2% overall performance improvement and 13.3% system energy reduction compared with the traditional stop-go method.