OPAMP: Evaluation Framework for Optimal Page Allocation of Hybrid Main Memory Architecture

Main memory as a hybrid between DRAM and nonvolatile memory is rapidly considered as a basic building block of computing systems. Despite widely-performed researches no one can confirm whether hybrid memory is at its full performance in terms of energy consumption, time delay or both. The main problem is that evaluating their performance in comparison with the optimal performance is challenging since deriving the optimal value is NP-complete. In this paper, we design and implement an evaluation framework termed OPAMP, which calculates optimal performance of the hybrid memory environment. This system gathers workload, specification of DRAM and PRAM, and environmental parameters of the hybrid main memory. After that, it calculates the maximum performance under the corresponding conditions. We suggest the way of deriving the optimal value by profiling instead of page migration which is the mainstream of recent researches on hybrid main memory system. Also, proportion of DRAM's size to PRAM's and proportion of DRAM's usage space to PRAM's are impactive factors. While designing hybrid main memory, those two variables must be determined carefully and OPAMP gives the guideline to the researchers.