Improving energy efficiency of write-asymmetric memories by log style write

The significant scaling challenges of conventional memories, i.e., SRAM and DRAM, motivated the research on emerging memory technologies. Many promising memory technology candidates, however, suffer from a common issue in their write operations: the switching processes at different write operations (i.e., 0 → 1 and 1 → 0) are asymmetric. Using a pessimistic design corner to cover the worst case of a write operation incurs large power and performance cost in the existing emerging memory technology designs. In this work, we propose a universal log style write methodology to mitigate this asymmetry issue by operating two switching processes in separate stages. The dedicated design optimizations are allowed on either switching process. The simulation results on the spin-transfer-torque random access memory based last-level cache show that our technique can improve the system performance by 4% while receiving 35% power reduction on average 1. © 2012 ACM.