Hybrid L2 NUCA Design and Management Considering Data Access Latency, Energy Efficiency, and Storage Lifetime

Nonvolatile magnetic RAM (MRAM) offers high cell density and low leakage power. This paper reports on using a 3-D integration technology based on through-silicon vias, to stack disparate memory technologies (e.g., SRAM and MRAM) together onto chip multiprocessors. In this paper, we explore the design of a 3-D stacked nonuniform hybrid SRAM/MRAM L2 cache architecture (NUCA) using the on-chip network to mitigate the interconnection problem. In addition, this paper investigates the problem of partitioning shared SRAM/MRAM hybrid L2 cache and placing cache data into the partitioned 3-D stacked hybrid NUCA for concurrently executing multiple applications in order to improve the system performance in terms of instructions per second while considering the heterogeneous characteristics in interconnection wire delay, memory cell density, memory access latency, and memory power consumption in a 3-D stacked hybrid SRAM/MRAM L2 cache. Experimental results show that the proposed runtime method with a 3-D stacked hybrid L2 cache improves performance by 61%, energy efficiency, i.e., energy-delay product by 53%, and storage lifetime by 15.6 times on average compared with the conventional SRAM-only L2 cache or MRAM-only L2 cache with the similar area.