HMC-Sim: A Simulation Framework for Hybrid Memory Cube Devices

The recent advent of stacked die memory and logic technologies has lead to a resurgence in research associated with fundamental architectural techniques. Many architecture research projects begin with ample simulation of the target theoretical functions and approach. However, the logical and physical nature three-dimensional stacked devices, such as the Hybrid Memory Cube (HMC) specification, fundamentally do not align with traditional memory simulation techniques. As such, there currently exists a chasm in the capabilities of modern architectural simulation frameworks. This work introduces a new simulation framework developed specifically for the Hybrid Memory Cube specification. We present a set of novel techniques implemented on an associated development framework that provide an infrastructure to flexibly simulate one or more Hybrid Memory Cube stacked die memory devices attached to an arbitrary core processor. The goal of this development infrastructure is to provide architectural simulation frameworks the ability to begin migrating current banked DRAM memory models to stacked HMC-based designs without a reduction in simulation fidelity or functionality. In addition to the core simulation architecture, this work also presents a series of memory workload test results using the infrastructure that elicit device, vault and bank utilization trace data from within a theoretical device. These evaluations have confirmed that HMC-Sim can provide insightful guidance in designing and developing highly efficient systems, algorithms, and applications, considering the next-generation three-dimensional stacked memory devices. HMC-Sim is currently open source, licensed under a BSD-style license and is freely available to the community.