Explanation of 90% Line in the performance testing tool JMeter aggregation report

90% of the Line in the aggregate report involves the concept of percentiles, which is a statistical term and is defined as follows:

If you sort a set of data from large to small and calculate the corresponding cumulative percentile, the value of the data corresponding to a 100 percentile is called the percentile. Can be expressed as: a group of n observations arranged according to numerical size, for example, the value in the p% position is called the p percentile.

For example, the median represents the 50th percentile. So 90%Line is easy to understand, that is, a group of numbers are arranged from small to large, and find his 90th number P, then 90% of the numbers in this array will be less than or equal to P, and (1-90%) of the numbers will be greater than or equal to P. The response time of 90%Line in the performance test is very meaningful, which is used to indicate that the response time of 90% users will not exceed P seconds.

Example 1: if there are the following 10 numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, arrange them from big to small.

Find that its 90th percentile, that is, the ninth number happens to be 9, then his 90%Line is 9.

Cases 2:1, 2,2.5,3,3.6,3.7,4,4.2,4.3,4.3,4.7,5,5.2,5.4,5.8,5.9,6,8,15,23,29. Sort them from big to small.

Find its 90th percentile, the 18th number is 15, and his 90%Line is 12.