I have two load testing applications I'm trying on my web server, JMeter and another one which is called Web Applications Testing (WAPT) from http://www.loadtestingtool.com/.
Now the thing is I have noticed several weird results under JMeter which I have a hard time explaining, and it seems the other tool does not have the same results.
First off, I do a simple test, loading my home page (index.jsp) with 10 concurrent users and have 10 seconds of delay between each iteration. The first weird thing is that I noticed (this is very obvious viewing the graph results) that the responses are slow at first and keep improving over time. Like the first 100 samples are about 2 to 3 times slower than after 1000 samples for example. So at first the page takes around 10 seconds and eventually (around the 1000th sample) takes 3 seconds roughly.
Now I thought maybe this is a behavior of the server somehow, but using the other tool (a windows app) I get very consistent results, around 2.5 seconds for loading my page.
So my question, why does JMeter starts slow like that and improve over time?? Obviously this is not due to my application as proved by the other tool... I run JMeter with the xms to 256 and xmx384, but anyways for only 10 users I would not expect it to use too much resources. I have no other resource eating result either... Any clues on what's happening here??