Need help in open source performance testing tool

Hi All, 

This is regarding the performance testing tool. Other than Open STA and JMeter what are the open source tools available and which one is good. When I used the Open STA and JMeter, my application is not supporting it. Moreover Open STA supports Netscape and IE4, 5 and 6 versions. But I'm using IE 7 and the application is not supported in other versions of IE. 

Can anyone help me in this? It will be very helpful for me and I can proceed according to that. 

Thanks in advance..

Thank you,

Deepak