Reliability aware dynamic voltage and frequency scaling for improved microprocessor lifetime

Dynamic voltage and frequency scaling (DVFS) is heavily used for power management in real-time environments. Although the schemes leveraging DVFS provide significant power reduction, adverse effects on chip reliability are possible. Alternate increase and decrease in operating voltage and frequency leads to thermal cycling. Increasing transistor packing density leads to a larger range of possible operating temperatures, exacerbating the thermal cycling problem. Also, the chip reliability quantification process does not include and represent the effects of small scale thermal cycles. A good number of in-field chip failures are attributed to the consequences of these. Thus, it is imperative to include their effects into the processor voltage and frequency selection process. Our work develops an integrated processor thermal and performance management technique centered on novel polynomial time scheduling algorithms that lead to lowering of thermal cycles in soft real time environments. Our technique leverages application awareness and runtime monitoring for improving chip lifetime, while achieving considerable energy savings. We show that a significant reduction in thermal cycles and peaks is possible, leading to longer chip life expectations.