MemorySim: An RTL-level, timing accurate simulator model for the Chisel ecosystem

Abstract: The rapid growth of AI applications has driven increased demand for specialized AI hardware, highlighting critical opportunities within the memory subsystem, which often serves as a performance bottleneck in high-demand workloads such as LLMs. Existing high-level memory simulators, such as DRAMSim2 and DRAMSim3, offer timing simulations but frequently compromise on correctness or integration at the register-transfer level (RTL). We present MemorySim, an RTL-level memory simulator designed to deliver both accurate timing and functional correctness. MemorySim integrates seamlessly with existing Chisel and Verilog simulations and is fully compatible with the Chisel/Chipyard ecosystem. This enables users to obtain precise performance and power estimates, supporting downstream evaluation through simulation platforms such as FireSim.