79. Pmbench: A Micro-Benchmark for Profiling Paging Performance on a System with Low-Latency SSDs

Modern non-volatile memory storage devices operate significantly faster than traditional rotating disk media. Disk paging, though never intended for use as an active memory displacement scheme, may be viable as a cost-efficient cache between main memory and sufficiently fast secondary storage. However, existing benchmarks are not designed to accurately measure the microsecond-level latencies at which next-generation storage devices are expected to perform. Furthermore, full exploitation of disk paging to fast storage media will require considerations in the design of operating system paging algorithms. This paper presents pmbench – a multiplatform synthetic micro-benchmark that profiles system paging characteristics by accurately measuring the latency of paging-related memory access operations. Also presented are sample pmbench results on Linux and Windows using a consumer NAND-based SSD and a prototype low-latency SSD as swap devices. These results implicate operating system-induced software overhead as a major bottleneck for system paging, which intensifies as SSD latencies decrease.