Report viewer not displaying any data for top level portfolio(folder )nearly 30000 records

Hi,

I have reportviewer control on reportsviewer.aspx page..where i am showing all my reports.

Reports accepts some parameters like portfolioName, depth, etc..

                                                    

From above screens if i select root and show report it is giving empty after 1  min 30 sec  but i tested directly from reports server it is working fine but taking 6 min (nearly 30000 records in my case)

but if select any sub folder then it is working fine even it is taking 2 to 5 min(but less than 10000 records)

Please can some one help me ,

Thanks