The Semantic Gap Between Software and the Memory System

The virtual memory system defined in the 1960s remains the primary interface between software and the physical memory system. Over time, operating systems and memory controllers evolved to become more intelligent about goals such as memory allocation, prefetching, security, and fairness. However, the limited knowledge that each side has of the other creates a significant semantic gap that may be artificially limiting the performance of todayâĂŹs memory systems. In this paper, we discuss the kinds of optimizations that occur on each side of the memory system and what types of knowledge could be shared between hardware and software to improve system performance.