tail latency
Tail latency describes the slow end of a response-time distribution.
Use this when Average latency looks healthy while some users wait much longer.
without the term
“The average response time looks fine, around 200ms, but some users complain it sometimes takes 10 seconds. How do we find those slow ones?”
with the term · How do you ask a model for tail latency?
Measure this endpoint’s tail latency under representative load. Trace the slow cases and compare percentiles after one targeted change.
What is tail latency?
Percentiles such as p95 and p99 describe the slowest requests. A healthy average can hide the one-in-a-hundred user who waits ten seconds.
Why does tail latency matter when vibe coding?
A benchmark of a few successful requests may hide queueing or dependency stalls.
How do you do tail latency?
Measure a representative distribution and trace the operations behind slow requests.
What goes wrong with tail latency?
Reporting p99 from too few samples to support a useful estimate.