Dynamic acceleration of multithreaded program critical paths in near-threshold systems

Near-Threshold Computing (NTC) is an effective technique to improve energy efficiency. However, single thread performance can suffer dramatically in NTC systems as cores must be run at low frequency to ensure proper operation. A potential way to solve this problem is to accelerate a core for a short period of time using dynamic voltage and frequency scaling (DVFS). This fast-mode execution option must be selectively applied so as to not sacrifice the overall efficiency of the NTC system. To this end, this paper presents a novel software framework to improve the performance of multithreaded programs through smart scheduling of the fast mode cores. Our framework statically analyzes a target application and instruments dynamic monitoring and priority management code into the program. At runtime, the probabilistic scheduler assigns the cores to the fast mode according to the priority set by the instrumented code. In this way, the program critical path is dynamically accelerated by spending more time in the fast mode so that the overall performance gets improved.