Criterium measures the computation time of an expression. It is designed to address some of the pitfalls of benchmarking, and benchmarking on the JVM in particular.

This includes: - statistical processing of multiple evaluations - inclusion of a warm-up period, designed to allow the JIT compiler to optimise its code - purging of gc before testing, to isolate timings from GC state prior to testing - a final forced GC after testing to estimate impact of cleanup on the timing results.

Collecting benchmark results is the first step to solving disk I/O performance problems. Unfortunately, many bug reports and performance investigations fall down at the first step because bogus benchmark data is collected. This post explains common mistakes when running disk I/O benchmarks.

Time is Money. Understanding application responsiveness and latency is critical but good characterization of bad data is useless. Gil Tene discusses some common pitfalls encountered in measuring latency and response time behavior. He introduces how simple, open sourced tools can be used to improve and gain higher confidence in both latency measurement and reporting.