Coordinated omission
why your p99 is not about your service
What people expectThat a percentile is a property of the service. It is a property of the instrument: the same service measured by a closed-loop generator and by a fixed schedule produces p99s that differ by two orders of magnitude, and only one of them is what a user would have felt.
The numbers
- intended rate per sec
- 1,000 req/s
- service time ms
- 0.2 ms
- workers
- 10
- pause every sec
- 2.5 s
- window sec
- 5 s
- omission correction
- 0
- seed
- 20260730
The mechanism is documented; these particular values are authored, chosen to put the interesting threshold somewhere you can see it. The simulation is deterministic and seeded — the same spec renders the same frames on any machine.