Method and apparatus for tracking thread stacks during a trace of a computer program. Hardware assistance mechanisms allow a processor to autonomically maintain a thread work area for each thread where a call stack is stored. An operating system informs the processor of the size of the data area to allocate to a particular thread work area. When a trace of a computer program is to be performed, trace software, informs the processor to begin maintaining thread call stack information in the thread work area. For each thread in the computer program execution, the processor maintains a work area having a size that is determined based on the size communicated by the operating system. The processor contains microcode to cause the processor to automatically store thread tracking information in the work areas designated by control registers of the processor when a control bit is set.