SQL 2005 Reporting Services seems to process reports sequentially

I'm trying to profile the experience of multiple users of a web application, all trying to generate reports at the same time. The reports are displayed on a web page using the report viewer control. The execution log on the re开发者_运维问答port server seems to indicate that the reports are executed sequentially (one at a time).

Is this the expected behavior?

Is there a way to tweak this behavior? Maybe some configuration file on the report server. Or something in the way the requests for the reports are issued?

I know I can use report caching, and optimize the report execution itself. But I need to address the case where multiple users ask for a "fresh" copy of their report (different for each user), and the report execution takes 30-60 seconds.

Is there any other technique to speed things up?

Can you check you have accidentally checked the User Single Transaction option on the data source.