How to perform load testing on sharepoint 2010 site without external tools ? Does developer dashboard provide load options ? I am aware of load runner and other tools .
There aren't any tools built-in for making artificial loads on the SharePoint servers. You would need to use or create a tool for making requests against SharePoint.
You can, however, use Performance Monitor in Windows to monitor specific performance metrics from SharePoint. Start with http://technet.microsoft.com/en-us/library/ff758658(v=office.15).aspx for more information on monitoring SharePoint performance with Performance Monitor.
You need to create something yourself, using Visual Studio.
There are numerous resources online. Take a look at Web performance and load testing SharePoint 2010 and 2013 applications, as well as SharePoint Performance Tests and MOSS Load Test (Codeplex projects) for inspiration.