An-I Andy Wang
UCLA, The Laboratory for Advanced Systems Research
Geoffrey H. Kuenning
Harvey Mudd College
Peter Reiher and
Gerald J. Popek
UCLA, The Laboratory for Advanced Systems Research
File System Performance has been greatly influenced by disk caching mechanisms. As the size of memory increases, common workloads are more likely to run completely from memory, and the effects of L2 caching and underlying hardware are becoming more visible.
This paper investigates performance anomalies observed when measuring and comparing the memory performance of various leading file systems. We discovered that without considering the effects of L2 caching policy, memory footprints of file systems, states of L2 cache, and memory page alignments, existing microbenchmarks could produce numbers that are significantly misleading and could result in poor designs and improper conclusions about relative file system performance.
We recommend that the design of file system microbenchmarks for memory-rich environments should carefully consider the initial states of memory and L2 cache, subtle warm-up effects, the cache eviction policy, interactions between workload size and the memory and cache sizes, and the management granularity of memory and the L2 cache.