计算 TP90TP99TP...

• what-do-we-mean-by-top-percentile-or-tp-based-latency
  
  tp90 is a minimum time under which 90% of requests have been served. Imagine you have times:

10s
1000s
100s
2s

Calculating TP is very simple:

- sort all times in ascending order: [2s, 10s, 100s, 1000s]

- find latest item in portion you need to calculate. For TP50 it will ceil(4.5)=2 requests. You need 2nd request. For TP90 it will be ceil(4.9)=4. You need 4th request.

- get time for the item found above. TP50=10s. TP90=1000s

• Java code

private static int tp(List<Integer> times, int percent) {
        float percentF = (float)percent/100;
        int index = (int)(percentF * times.size() - 1);
        Collections.sort(times);
        return times.get(index);
}