web i report tuning ( performance)

Hello Experts,

I Have a web i report built over BEX query, When ever i execute bex query it is taking 15 seconds(DEV) to display result. But, in Infoview if i refresh the WEb I report it is taking 2 min of time. How can i tune the web i report from universe level. Could anyone suggest me any documents or throw some light on performance tuning.

Prashanth