AYUSH: Extending Lifetime of SRAM-NVM Way-Based Hybrid Caches Using Wear-Leveling

The features and limitations of both SRAM and NVM (non-volatile memory) technologies have led the researchers to study SRAM-NVM way-based hybrid last level caches (LLCs). Since large leakage power consumption of SRAM allows including only few SRAM ways, the small write-endurance of NVM may still lead to small lifetime of these hybrid caches. We propose AYUSH, a technique for improving lifetime of SRAM-NVM hybrid caches. AYUSH uses data-migration approach to preferentially utilize SRAM for storing write-intensive data. Microarchitectural simulations have shown that AYUSH provides larger improvement in lifetime than three previous techniques. For single, dual and quad-core system configurations, the average increase in cache lifetime with AYUSH is 6.90×, 24.06× and 47.62×, respectively. Also, it does not harm performance or energy efficiency and works well for a range of system and algorithm parameters.