SharePoint 2010 - Developer Dashboard

Great tool for troubleshooting SharePoint 2010 page performance - you can easily capture bad performing web parts and page loads. Even grab a correlation id that can be traced back to ULS logs. To turn on 


STSADM:
Mode ON
STSADM –o setproperty –pn developer-dashboard –pv On
Mode OFF
STSADM –o setproperty –pn developer-dashboard –pv Off
Mode ONDEMAND
STSADM –o setproperty –pn developer-dashboard –pv OnDemand
                      
PowerShell:
$DevDashboardSettings = [Microsoft.SharePoint.Administration.SPWebService]::ContentService.DeveloperDashboardSettings;
$DevDashboardSettings.DisplayLevel = 'OnDemand';
$DevDashboardSettings.RequiredPermissions = 'EmptyMask';
$DevDashboardSettings.TraceEnabled = $true;
$DevDashboardsettings.Update() 


I use the OnDemand mode, SharePoint displays a small icon beside the Welcome web part. 


Clicking this icon will open the Developer Dashboard at the base of the page and show timings etc