PREMSim: A Resilience Framework for Modeling Traditional and Emerging Memory Reliability

Scaling limitations of conventional and emerging memories has provided the impetus for the increased focus on reliability techniques to overcome associated physical limitations of non-perfect devices. However, despite these reliability advances, critical challenges remain to be solved as new memory types and memory vulnerabilities arise. There continues to be no simulator with extended reliability models for easy comparison of existing and newly developed techniques nor simple integration of innovative new reliability concepts and failure modes. The mission of our simulator, PremSim, is to provide a framework which solves these fundamental limitations. While PremSim can function using memory traces, it was also designed from the ground-up to be fully integrated with several external simulators including the Structural Simulation Toolkit (SST) as a memory backend. It can connect to other detailed memory backends such as DRAMSim2 for detailed energy and timing. Further, it provides modes which give estimated lifetime for endurance-limited memories, as well as the provable correction capability per row for a given fault distribution. To perform these calculations in a reasonable time window and to remain compatible with abstract full-system simulators, we also provide and verify novel abstractions. Additionally, we show case studies of how different fault mitigation strategies can be modeled effectively in PremSim including solutions at the page, row, word, and bit-level granularity of next-generation traditional and emerging faulty memories.