https://idle-ti.me • This is a web feed, also known as an Atom feed. Subscribe by copying the URL from the address bar into your newsreader. Visit About Feeds to learn more and get started. It's free. Visit website Recent posts Updated on $DATE date load testing Performance engineering & observability — articles, curated tools, and projects by Jérôme Ramette. Zola2026-05-04T00:00:00+00:00https://idle-ti.me/tags/load-testing/atom.xml 2026-05-04T00:00:00+00:00 2026-05-04T00:00:00+00:00 Jérôme Ramette https://idle-ti.me/blog/coordinated-omission/

Most HTTP benchmarking tools quietly hide tail latency when the server slows down. The phenomenon is called coordinated omission, it shows up almost exclusively in p99 and beyond, and it has caused production incidents at organisations that thought their load tests were green. This post explains the mechanism, demonstrates it empirically with a reproducible benchmark of eight tools across five server pathologies, and shows how to fix it with a constant arrival-rate workload model.