Opportunistic Turbo Execution in NTC: Exploiting the paradigm shift in performance bottlenecks

In this paper, we investigate an intriguing shifting trend in performance bottlenecks for Near-Threshold Computing (NTC) processors. Our study demonstrates that the traditional memory latency bottleneck is largely superseded by the bottlenecks of Long Latency Datapaths (LLDs) within a processor core. To exploit this paradigm shift, we propose Opportunistic Turbo Execution (OTE). OTE dynamically boosts the performance of LLDs, by several factors, improving both performance and energy efficiency in an NTC core. Using a comprehensive circuit-architectural analysis, we demonstrate a 42.2% improvement in energy efficiency over a recently proposed technique, across a range of benchmarks.