VaMV: Variability-aware Memory Virtualization

Power consumption variability of both on-chip SRAMs and off-chip DRAMs is expected to continue to increase over the next decades. We opportunistically exploit this variability through a novel Variability-aware Memory Virtualization (VaMV) layer that allows programmers to partition their application's address space (through annotations) into virtual address regions and create mapping policies for each region. Each policy has different requirements (e.g., power, fault-tolerance) and is exploited by our dynamic memory management module (VaMVisor), which adapts to the underlying hardware, prioritizes the memory resources according to their characteristics (e.g., power consumption), and selectively maps data to the best-fitting memory resource (e.g., high-utilization data to low-power memory space). Our experimental results on embedded benchmarks show that VaMV is capable of reducing dynamic power consumption by 63% on average while reducing total execution time by an average of 34% by exploiting: 1) SRAM voltage scaling, 2) DRAM power variability, and 3) Efficient dynamic policy-driven variability-aware memory allocation.