Developer dashboard is one of the coolest features in SharePoint 2010 for enhancing the developers productivity.
Developer dashboard has the same concept like the ASP.NET trace which can be enabled on a page to view more information that helps the developer. Developer dashboard helps the developers a lot in performance tuning and troubleshooting issues related to page rendering.
How to enable Developer dashboard
Run the following stsadm command using the command prompt.
stsadm -o setproperty -pn developer-dashboard -pv ondemand
After successfully running the previous command, you should be able to see "Toggle Developer Dashboard” button on the web page top right corner (check below), Click the button and the dashboard will appear at the bottom of the page.
What Developer Dashboard shows?
- Requests with timings for each one.
- Database queries and their response times.
- Load times for each Web Part on the page and Pre-render time.
- Number of Web server SPRequest(s) and their timing.
- Any critical events.
Screen shot for the developer dashboard which appears in the below of your web page
Requests information:
- Url
- Total time
- Total size
- Breakdown for the request
Asserts and Critical events

Web parts on the page events and their timings

List of All database queries and their timings, clicking on the database query will show the query text (procedure name and passed parameters)
Note: You can view the usual ASP.NET trace by clicking “Show or hide additional tracing information . . .” at the bottom of the developer dashboard.
Related Links:
Using the Developer Dashboard in SharePoint 2010