Dynamic Cache Pooling in 3D Multicore Processors

Resource pooling, where multiple architectural components are shared among cores, is a promising technique for improving system energy efficiency and reducing total chip area. 3D stacked multicore processors enable efficient pooling of cache resources owing to the short interconnect latency between vertically stacked layers. This article first introduces a 3D multicore architecture that provides poolable cache resources. We then propose a runtime management policy to improve energy efficiency in 3D systems by utilizing the flexible heterogeneity of cache resources. Our policy dynamically allocates jobs to cores on the 3D system while partitioning cache resources based on cache hungriness of the jobs. We investigate the impact of the proposed cache resource pooling architecture and management policy in 3D systems, both with and without on-chip DRAM. We evaluate the performance, energy efficiency, and thermal behavior for a wide range of workloads running on 3D systems. Experimental results demonstrate that the proposed architecture and policy reduce system energy-delay product (EDP) and energy-delay-area product (EDAP) by 18.8% and 36.1% on average, respectively, in comparison to 3D processors with static cache sizes.