Improving Non-Volatile Memory Lifetime through Temporal Wear-Limiting

Non-volatile memory technologies provide a low-power, high-density alternative to traditional DRAM main memories, yet all suffer from some degree of limited write endurance. The non-uniformity of write traffic exacerbates this limited endurance, causing write-induced wear to concentrate on a few specific lines. Wear-leveling attempts to mitigate this issue by distributing write-induced wear uniformly across the memory. Orthogonally, wear-limiting attempts to increase memory lifetime by directly reducing wear. In this paper, we present the concept of temporal wear-limiting, in which we exploit the trade-off between write latency and memory lifetime. Using a history of the slack between per-bank write operations, we predict future write latency, allowing for up to a 1.5x memory lifetime improvement. We present two extensions for improving the effectiveness of this history-based mechanism: a method for dynamically determining the optimum history size, and a method for increasing lifetime improvement through address prediction