A method, apparatus, and a computer program product are disclosed for selectively activating a trace function in a computer program in response to a call of a predetermined trigger code element so that trace data is produced only for those subroutines that call the trigger code element or are called by the trigger code element. The computer program product provides one or more trace code elements for one or more selected subroutines of the computer program stored on internal memory of a digital computer. The trace code elements provide trace data for said selected subroutines. The computer program product also selects a subroutine as a trigger code element, processes the computer program, monitors the call stack for the trigger code element, and enables the trace code elements for each selected subroutine simultaneously present in the call stack if the trigger code element is identified in the call stack.