RRAMulator: An efficient FPGA-based emulator for RRAM crossbar with device variability and energy consumption evaluation

Abstract

The in-memory computing (IMC) systems based on emerging technologies have gained significant attention due to their potential to enhance performance and energy efficiency by minimizing data movement between memory and processing unit, which is especially beneficial for data-intensive applications. Designing and evaluating systems utilizing emerging memory technologies, such as resistive RAM (RRAM), poses considerable challenges due to the limited support from electronics design automation (EDA) tools for rapid development and design space exploration. Additionally, incorporating technology-dependent variability into system-level simulations is critical to accurately assess the impact on system reliability and performance. To bridge this gap, we propose RRAMulator, a field-programmable gate array (FPGA) based hardware emulator for RRAM crossbar array. To avoid the complex device models capturing the nonlinear current–voltage (IV) relationships that degrade emulation speed and increase hardware utilization, we propose a device and variability modeling approach based on device measurements. We deploy look-up tables (LUTs) for device modeling and use the multivariate kernel density estimation (KDE) method to augment existing data, extending data variety and avoiding repetitive data usage. The proposed emulator achieves cycle-accurate, real-time emulations and provides information such as latency and energy consumption for matrix mapping and vector–matrix multiplications (VMMs). Experimental results show a significant reduction in emulation time compared to conventional behavioral simulations. Additionally, an RRAM-based discrete Fourier transform (DFT) accelerator is analyzed as a case study featuring a range of in-depth system assessments.