Hi Vishal,
I don't think there is option for specific site collection or web application,but there is option of enabling developer dashboard on specific master pages and that is one on of the way you could do it.
look article on below link to enable developer dashboard on specific master pages
https://msdn.microsoft.com/en-us/library/office/ff512745%28v=office.14%29.aspx?f=255&MSPPError=-2147217396
Let me know if this helps.
Thanks
Bhism
Hello Vishal,
Developer dashboard cannot be enabled / disabled on a specific web application. It is applied across the Farm.
See another thread on the same - Link
kindly mark it as answer if this helps you.
-Hatim
- Marked as answer by VishalGoyal247 2 hours 48 minutes ago
Hi,
Please check the following link on Developer Dashboard.
http://sharepointkitchen.blogspot.in/2014/04/developer-dashboard-in-sharepoint.html
Don't forget to mark it as an Answer if it resolves your issue and Vote Me as helpful if it useful.