Method and system for performance monitoring in a multithreaded processor

A method and system for performance monitoring within a multithreaded processor are provided. The system includes a processor responsive to instructions within first and second threads and a performance monitor that separately records a first event generated by the processor in response to the first thread and a second event generated by the processor in response to the second thread. In one embodiment, the processor has first and second modes of operation. In this embodiment, when the performance monitor is operating in the first mode, a first counter within the performance monitor increments in response to each occurrence of the first event and a second counter within the performance monitor increments in response to each occurrence of the second event. Alternatively, when the performance monitor is operating in the second mode, the first counter increments in response to each occurrence of the first event and in response to each occurrence of the second event.