The use of marker(s) in the source code of a program under evaluation. A representation of the marker(s) remains in the binary version of the program under evaluation. During execution, upon executing the marker, data is gathered regarding the timeline of the execution of the marker in the context of overall timeline of execution. A visualization of the marker is then displayed that illustrates the execution of the marker in the context of a larger timeframe of execution. Optionally, the marker may be associated with text, or other data, at least some of which being rendered with the visualization. Accordingly, an application developer, or indeed anyone evaluating the program, may place markers within source code and/or evaluate the timeline of execution of those markers.