calculating the percentile in java
/**
* A simple method to log 95th percentile information
*/
private static void logPercentileInfo() {
double total = 0;
for (Map.Entry<Long, Long> entry : CassandraTimer.histogram.entrySet()) {
long value = entry.getKey() * entry.getValue();
total += value;
}
double sum = 0.95*total;
double totalSum = 0;
SortedSet<Long> keys = new TreeSet<Long>(CassandraTimer.histogram.keySet());
for (long key : keys) {
totalSum += CassandraTimer.histogram.get(key);
if(totalSum >= sum) {
//this is the 95th percentile I guess
System.out.println(key);
}
}
}