Product & Analytics / Performance & Reliability
Percentile Latency p50 / p95 / p99 (also "tail latency", "response-time percentiles")
The response time below which a given share of requests fall -- a tail-aware read on speed, unlike an average.
The fork, why two teams get different numbers
WHICH percentile and OF WHAT population.
In the Metric Library
- The full fork, both definitions worked all the way through
- The trap that makes the number lie, on a real export
- Every formula variant, spelled out
- The reconciliation anchor, what to tie it to and when to refuse
Reference: Site-reliability / performance-engineering convention (no governing body); t-digest and HDR-histogram percentile-merging methods cited as reference