You work in a company which uses SQL Server 2008. You are the administrator of the company database. Now you are in charge of a SQL Server 2008 instance. The instance contains a database named DB1. An application which is continuously connected uses DB1. The application extensively uses the INSERT command and triggers the population of multiple tables. Now you notice that the application has a poor performance. You doubt that this problem has something to do with blocking. You have to monitor the state of the instance at regular intervals while not affecting the application performance further.  Which tool should you use? （）