Energy-efficient multithreading for a hierarchical heterogeneous multicore through locality-cognizant thread generation

• Innovative graph-based locality-aware threading techniques offer EDP reductions.
• Techniques are tailored to the novel heterogeneous Passive/Active Multicore (PAM).
• Automatic partitioning techniques offer up to 48% EDP reduction with PAM.

Energy costs have become increasingly problematic for high performance processors, but the rising number of cores on-chip offers promising opportunities for energy reduction. Further, emerging architectures such as heterogeneous multicores present new opportunities for improved energy efficiency. While previous work has presented novel memory architectures, multithreading techniques, and data mapping strategies for reducing energy, consideration to thread generation mechanisms that take into account data locality for this purpose has been limited. This study presents methodologies for the joint partitioning of data and threads to parallelize sequential codes across an innovative heterogeneous multicore processor called the Passive/Active Multicore (PAM) for reducing energy consumption from on-chip data transport and cache access components while also improving execution time. Experimental results show that the design with automatic thread partitioning offered reductions in energy-delay product (EDP) of up to 48%.