FPGA-Based Emulation of Embedded DRAMs for Statistical Error Resilience Evaluation of Approximate Computing Systems

Embedded DRAM (eDRAM) requires frequent power-hungry refresh according to the worst-case retention time across PVT variations to avoid data loss. Abandoning the error-free paradigm, by choosing sub-critical refresh rates that gracefully degrade the eDRAM content, unlocks considerable power-saving opportunities, but requires to understand the effect of stochastic memory errors at the system/application level. We propose an FPGA-based platform featuring faulty eDRAM emulation based on advanced retention time models and silicon measurements for statistical error resilience evaluation of applications in a complete embedded system. We analyze the statistical QoS for various benchmarks under different sub-critical refresh rates and retention time distributions.