What does P99 latency represent? I keep hearing about this in discussions about an applications performance but couldn't find a resource online that would talk about this.
Tomasz Nurkiewicz
It's 99th percentile. It means that 99% of the requests should be faster than given latency. In other words only 1% of the requests are allowed to be slower.
We can explain it through an analogy, if 100 students are running a race then 99 students will complete the race in "latency" time.
来源：https://stackoverflow.com/questions/12808934/what-is-p99-latency