Hi Raju,
Seems period wise source cube have huge data, its taking more time to display results.
Performance point of view, pls recheck below points.
1.Creating aggregates
2. After loading data to cube, need to create index
3. if you have huge data, think about partition on 0CAMLMONTH or 0FISPER base.
4. compression old requests
5. use very less chars initial view of report results.
6. Try to generate your query thru RSRT, you will know where its take more time.
Thanks