Application Adaptive Energy Efficient Clustered Architectures

As clock frequency and die area increase, achieving energy efficiency, while distributing a low skew, global clock signal becomes increasingly difficult. Challenges imposed by deep-submicron technologies can be alleviated by using a multiple voltage/multiple frequency island design style, or otherwise called, globally asynchronous, locally synchronous (GALS) design paradigm. This paper proposes a clustered architecture that enables applicationadaptive energy efficiency through the use of dynamic voltage scaling for application code that is rendered non-critical for the overall performance, at run-time. As opposed to task scheduling using dynamic voltage scaling (DVS) that exploits workload variations across applications, our approach targets workload variations within the same application, while on-the fly classifying code as critical or non-critical and adapting to changes in the criticality of such code portions. Our results show that application adaptive variable voltage/variable frequency clustered architectures are up to 22 % better in energy and 11 % better in energy-delay product than their nonadaptive counterparts, while providing up to 31 % more energy savings when compared to DVS applied globally