WIRE: Write Energy Reduction via Encoding in Phase Change Main Memories (PCM)
Phase-change memory (PCM) suffers from high write energy consumption and limited endurance. To address these challenges, this paper proposes a low-overhead encoding scheme: a dynamic frequent-value-stack-based encoding that ensures most writes induce only a single-bit flip; combined with block-level wear leveling and differential bit rotation, it achieves effective write distribution. The core techniques include frequent value identification, Hamming distance optimization, bit-flip minimization, and efficient encoding storage. Experimental evaluation under multithreaded and multiprogrammed workloads demonstrates that the proposed approach reduces write energy by 38.2% on average, decreases bit flips by 41.7%, and extends PCM lifetime by 2.3×, significantly improving main memory energy efficiency and reliability.