HCI-tolerant NoC router microarchitecture

Abstract

The trend towards massive parallel computing has necessitated the need for an On-Chip communication framework that can scale well with the increasing number of cores. At the same time, technology scaling has made transistors susceptible to a multitude of reliability issues (NBTI, HCI, TDDB). In this work, we propose an HCI-Tolerant microarchitecture for an NoC Router by manipulating the switching activity around the circuit. We find that most of the switching activity (the primary cause of HCI degradation) are only concentrated in a few parts of the circuit, severely degrading some portions more than others. Our techniques increase the lifetime of an NoC router by balancing this switching activity. Compared to an NoC without any reliability techniques, our best schemes improve the switching activity distribution, clock cycle degradation, system performance and energy delay product per flit by 19%, 26%, 11% and 17%, respectively, on an average.

An enhanced planned obsolescence attack by aging networks-on-chip

“…NoC suffers from various device level aging effects, including negative bias temperature instability (NBTI) [6], [7], hot carrier injection (HCI) [8], [9], and electromigration (EM) [10]. These aging effects cause transistor and/or wire links wear-out.…”

“…Hot carrier injection (HCI) in MOSFETs occurs when a carrier from silicon channel is injected into the gate dielectric layer [9], and it can permanently change the switching characteristics of the transistor, including V th shifting and switching frequency degradation. In general, HCI poses a great reliability challenge to n-type transistors [8].…”

Scalable techniques for extending lifetime reliability of manycore systems

“…Redundant resources available, within and across the cores, are exploited to improve lifetime reliability in [135][136][137]. An aging-aware routing to optimize lifetime reliability of the Network on Chip (NoC) based on mixed-integer linear programming or convex optimization is proposed in [138][139][140].…”