I'm profiling some computationally intensive code of mine, and was surprised to see that the function RtlpNtMakeTemporaryKey takes up a huge chunk of time. It's module is ntdll and the source file is Unknown. Is this a call which is waiting for my slow function to terminate or is it something which I can optimize?
Are you sure you have symbols for ntdll? It's possible that you don't, and RtlpNtMakeTemporaryKey is just the closet exported symbol name that your debugger can see to the real function or functions that are taking up so much time.
But yeah, you should focus on your code and who/why you're calling into ntdll so much.