Performance testing of vaadin portlet

Hi All,

I am new to vaadin . I wonder if anyone knows how to do load test on vaadin portlets .

Currently I am using Jmeter to test but not sure with the response I am getting , because the
in summary report decreases as I run my test suite multiple times with same number of threads and loops .

Any suggestions regarding this or information about any other better tool for load testing will be highly appreciated

thank you