I have created an application in C++ using MFC, and then one day I have executed this application using Intel VTunes just to monitor the performance of the application and to check where most of the time is consumed by my application. After analyzing I have found that about 40% of the time is consumed by my code and around 35% of the time is consumed by the ntdll.dll file. So, the point here I wants to know is that is this a normal behaviour. I mean is this consumption i.e. 35% of the total time justifiable. Can anyone tell me that which kind of responsibilities resides on ntdll.dll i.e which kind of functionalities is achieved through this dll file, so that I can sort things out in my case and be able to optimize the code.