Online Management of Hybrid DRAM-NVMM Memory for HPC

Abstract

Non-volatile main memories (NVMMs) offer a comparable performance to DRAM, while requiring lower static power consumption and enabling higher densities. NVMM therefore can provide opportunities for improving both energy efficiency and costs of main memory. Previous hybrid main memory management approaches for HPC either do not consider the unique characteristics of NVMMs, depend on high profiling costs, or need source code modifications. In this paper, we investigate HPC applications’ behaviors in the presence of NVMM as part of the main memory. By performing a comprehensive study of HPC applications and based on several key observations, we propose an online hybrid memory architecture for HPC. It only requires low-overhead sampling of memory accesses for its page placement decisions. The experimental results obtained through running a wide range of HPC applications show that the proposed architecture can service up to 88% of accesses from DRAM if 90% of the main memory is built from NVMM. The NVMM lifetime can also be extended by up to 90% compared to all-NVMM.