Rethinking Memory Management in Modern Operating System: Horizontal, Vertical or Random?

On modern multicore machines, the memory management typically combines address interleaving in hardware and random allocation in the operating system (OS) to improve performance of both memory and cache. The conventional solutions, however, are increasingly strained as a wide variety of workloads run on complicated memory hierarchy and cause contention at multiple levels. We describe a new framework (named HVR) in OS memory management to support a flexible policy space for tackling diverse application needs, integrating vertical partitioning across layers, horizontal partitioning and random-interleaved allocation at a single layer. We exhaustively study the performance of these policies for over 2,000 workloads and correlate performance with application characteristics. Based on this correlation we derive several practical rules of memory allocation that we integrate into the unified HVR framework to guide resource partitioning and sharing for dynamic and diverse workloads. We implement our approach in Linux kernel 2.6.32 as a restructured page indexing system plus a series of kernel modules. Experimental results show that our framework consistently outperforms the unmodified Linux kernel, with up to 21 percent performance gains, and outperforms prior solutions at individual levels of the memory hierarchy. [ABSTRACT FROM PUBLISHER]