Performance Index TP99 I solution _ performance

First give the answer to Google:

The Tp90 is a minimum time under which 90% to requests have been served.

Tp90 = Top Percentile 90

Imagine your have response times:

10s
1000s
100s
2s

Calculating TP is very simple:

1. Sort all times in ascending order: [2s, 10s, 100s, 1000s]

2. Find latest item in portion you need to calculate.
2.1 For TP50 It'll be ceil (4*0.5) = 2 requests. You need 2nd request.
2.2 For TP90 It'll be ceil (4*0.9) = 4. You need 4th request.

3. We have time for the item found above. Tp50=10s. tp90=1000s

In this way, TP99 is the minimum time consuming required to meet 99% of the network requests. The same TP999 is the minimum time consuming required to meet 999 per thousand of network requests.

For example: There are four requests that take time, respectively:

10ms,1000ms,100ms,2ms

So we can calculate the Tp99:4 request, 99% of the number of requests for 4*0.99, carry rounding is 4 times, to meet all the 4 requests of the minimum time to 1000ms, that is, the answer to TP99 is 1000ms.

If there is any mistake, welcome treatise.

From:http://www.cnblogs.com/guodongdidi/p/6018356.html