A Hybrid-Grained Remapping Defense Scheme Against Hard Failures for Row-Column-NVM

Row-column-NVM (RC-NVM) is a new architecture for emerging nonvolatile memory (NVM), such as ReRAM, PCM, and STT-RAM. It leverages the symmetry of crossbar structure and supports both row and column memory accesses. The new architecture is well fit for the applications with different access patterns which suffer from low efficiency and high-energy consumption in traditional memory architecture. However, existing hard failure defensive techniques for emerging NVM are inappropriate for RC-NVM. Therefore, the limited device endurance makes RC-NVM ephemeral and unreliable. In order to overcome this challenge, we propose a hybrid-grained remapping defensive technique to fight against hard failures. By hybrid-grained remapping, we can effectively avoid multiple reads issue of fine-grained remapping and low utilization issue of coarse-grained remapping and significantly increase RC-NVM lifetime with little performance loss. Moreover, motion vector and remap-aware write optimizations are also proposed to further improve RC-NVM reliability and degrade performance loss and energy consumption of write operation. An evaluation shows that the hybrid-grained remapping can increase the lifetime by 61.1% compared to single coarse-grained remapping with only 5% performance loss and 7% energy increase when 10% pages are mapped out. Optimizations can further improve lifetime, performance, and energy by 5%, 11.4%, and 30.5%, respectively.