Ramulator 2.0: A Modern, Modular, and Extensible DRAM Simulator

TL;DR

Ramulator 2.0 is a highly modular and extensible DRAM simulator that facilitates rapid implementation and evaluation of memory system design changes, supporting various DRAM standards and mitigation techniques.

Contribution

It introduces a flexible, human-readable specification syntax and reusable lambda functions, enabling easy extension and modification of DRAM models and controllers.

Findings

Supports multiple DRAM standards like DDR5, LPDDR5, HBM3, GDDR6

Allows modular implementation of RowHammer mitigation techniques

Maintains fast simulation speed with validated accuracy

Abstract

We present Ramulator 2.0, a highly modular and extensible DRAM simulator that enables rapid and agile implementation and evaluation of design changes in the memory controller and DRAM to meet the increasing research effort in improving the performance, security, and reliability of memory systems. Ramulator 2.0 abstracts and models key components in a DRAM-based memory system and their interactions into shared interfaces and independent implementations. Doing so enables easy modification and extension of the modeled functions of the memory controller and DRAM in Ramulator 2.0. The DRAM specification syntax of Ramulator 2.0 is concise and human-readable, facilitating easy modifications and extensions. Ramulator 2.0 implements a library of reusable templated lambda functions to model the functionalities of DRAM commands to simplify the implementation of new DRAM standards, including DDR5, LPDDR5, HBM3, and GDDR6. We showcase Ramulator 2.0's modularity and extensibility by implementing and evaluating a wide variety of RowHammer mitigation techniques that require different memory controller design changes. These techniques are added modularly as separate implementations without changing any code in the baseline memory controller implementation. Ramulator 2.0 is rigorously validated and maintains a fast simulation speed compared to existing cycle-accurate DRAM simulators. Ramulator 2.0 is open-sourced under the permissive MIT license at https://github.com/CMU-SAFARI/ramulator2