Enable Developer Performance Dashboard in Sharepoint 2010

when I developed a ListEvent in the Custom List. but i really want to know how is the event feature perform

in shaepoint 2010.

here is a line you can execute in the sharepoint 2010 server via CMD

"C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\BIN\stsadm.exe" -o setproperty -pn developer-dashboard -pv OnDemand

then restart the iis to allow the sharepoint to enable this feature.

after you click on the library, you can see a ICON in the top righ corner. when you cllick on the icon.
the dashboard will be shown in the button of the page with all performance information. those detail
 information will be great helpful for trouble shooting when you encounter performance related issue.