Sensor-wise Methodology to Face NBTI Stress of NoC Buffers

Abstract

Networks-on-Chip (NoCs) are a key component for the new many-core architectures, from the performance and reliability stand-points. Unfortunately, continuous scaling of CMOS technology poses severe concerns regarding failure mechanisms such as NBTI and stress-migration. Process variation makes harder the scenario, decreasing device lifetime and performance predictability during chip fabrication. This paper presents a novel cooperative sensor-wise methodology to reduce the NBTI degradation in the network on-chip (NoC) virtual channel (VC) buffers, considering process variation effects as well. The changes introduced to the reference NoC model exhibit an area overhead below 4%. Experimental validation is obtained using a cycle accurate simulator considering both real and synthetic traffic patterns. We compare our methodology to the best sensor-less round-robin approach used as reference model. The proposed sensor-wise strategy achieves up to 26.6% and 18.9% activity factor improvement over the reference policy on synthetic and real traffic patterns respectively. Moreover a net NBTI V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</inf> saving up to 54.2% is shown against the baseline NoC that does not account for NBTI.