90th Percentile response time

The 90th percentile response time value is the value for which 90% of the data points are smaller   and 10% are bigger.

To calculate the 90th percentile value:

1. Sort the transaction instances by their value.
2. Remove the top 10% instances.
3. The highest value left is the 90th percentile.

Consider the below example:

There are 10 instances of transaction “TRANSACTION 01” with the values
4 sec 2 sec 3 sec 1 sec 5 sec 17 sec 8 sec 7 sec 6 sec 10 sec

1. Sort values from best to worst:
    1 sec 2 sec 3 sec 4 sec 5 sec 6 sec 7 sec 8 sec 10 sec 17 sec

2. Remove top 10%, In our case i.e. value “17 sec”
   1 sec 2 sec 3 sec 4 sec 5 sec 6 sec 7 sec 8 sec 10 sec

3. The highest value left is the 90th percentile value i.e. “10 sec” is the 90th percentile value.