A Compression-Based Hybrid MLC/SLC Management Technique for Phase-Change Memory Systems

The storage density of PCM has been demonstrated to double through the employment of Multi-Level Cell (MLC) PCM arrays. However, this increase in capacity comes at the expense of increased latency (both read and write) and decreased long-term endurance, as compared to the more conventional Single-Level Cell (SLC) PCM. These negative traits of MLCs detract from the potentially invaluable storage benefits. This paper introduces a compression-based hybrid MLC/SLC PCM management technique that aims to combine the performance edge of SLCs with the higher capacity of MLCs in a hybrid environment. Our trace-driven simulations with real application workloads demonstrate that the proposed technique achieves 3.6X performance enhancement and 72% energy reduction, on average, as compared with MLC-only configurations, while always providing the same effective capacity as the MLC-only mode.