Characterizing and Modeling Nonvolatile Memory Systems

Scalable server-grade nonvolatile RAM (NVRAM) DIMMs are commercially available with the release of Intel’s Optane DIMM. Recent studies on Optane DIMM-based systems unveil discrepant performance characteristics, compared with what many researchers thought before the product release. To thoroughly analyze the source of the discrepancy and facilitate real-NVRAM-aware system design, we develop an NVRAM microarchitecture characterization and modeling framework, consisting of a Low-level profilEr for Non-volatile memory Systems (LENS) and a Validated cycle-Accurate NVRAM Simulator (VANS). LENS allows users to comprehensively analyze NVRAM performance attributes and reverse engineer NVRAM microarchitectures. We use LENS to reverse engineer the sophisticated microarchitecture design of Optane DIMM and generate a set of architecture implications of industrial NVRAMs. VANS models Optane DIMM microarchitecture and is validated by comparing with the detailed performance characteristics of Optane DIMM-attached servers. VANS adopts a modular design that can be easily modified to extend to other NVRAM architecture designs.