DTrace is often positioned as an operating system analysis tool for the system administrators, but it has a wider use than this. In particular the application developer may find some features useful when trying to understand a performance problem. In this article we show how DTrace can be used to print a list of the user-defined functions that are called by the target executable. We also show how often these functions are called. Our solution presented below works for a multithreaded application and the function call counts for each thread are given.