A system for displaying performance test information for software. The system includes a graphical user interface that displays information in a format to allow ready identification of performance problems and their causes. The interface includes a timeline view depicting activity levels during the execution of a program under test. Events during a sub-range of times during the program execution may be displayed with information revealing interactions of threads making up the program. Additional information may be displayed in a further display fields, including textual information. Much of the displayed information is represented graphically, allowing a performance engineer to quickly identify areas of the program to investigate further.