Optimizing data placement for reducing shift operations on Domain Wall Memories

Domain Wall Memory (DWM) using nanowire with data access port, exhibits extraordinary high density, low power leakage, and low access latency. These properties enable DWM to become an attractive candidate for replacing traditional memories. However, data accesses on DWM may require multiple shift operations before the port points to requested data, resulting in varying access latencies. Data placement, therefore, has a significant impact on the performance of data accesses on DWM. This paper studies compiler-based optimization techniques for data placement on DWM. To the authors´ best knowledge, this is the first work addressing data placement problem on DWM. We present an efficient heuristic, called Grouping-Based Data Placement (GBDP), for the data placement problem of a given data access sequence on DWM. The experimental results show that GBDP has a significant performance improvement; for example, GBDP reduces 82% shift operations on an 8-port DWM compared with non-optimized approach.