Content-aware encoding for improving energy efficiency in multi-level cell resistive random access memory

Memory is an integral and important component of both general-purpose and embedded systems. It is widely acknowledged that energy of the memory structure is a major contributor in overall system energy. Recent advances with emerging non-volatile memory (NVM) technologies can potentially alleviate the issue of memory leakage power. However, they introduce new challenges and opportunities for dynamic power management in memory. In this paper, we consider resistive random access memory (RRAM), a promising NVM technology, and observe that a specific feature of the memory, namely, its multi-level cell (MLC) structure, can be used to significantly reduce its read access energy. Unlike conventional CMOS static random access memory (SRAM), the read access energy in RRAM largely depend on the stored content. Based on this observation, we present an efficient encoding technique for improving the energy efficiency for multi-level cell RRAM. Our simulation results with benchmark applications demonstrate an order-of-magnitude energy reduction with modest area overhead.