Processor core having a saturating event counter for making performance measurements

Abstract

A performance monitor including a saturating counter provides a relative measure of event frequency without requiring a minimum polling rate or periodic reset to avoid or account for counter overflow. The saturating counter is incremented upon detection of an event and decremented if an event is not detected within a predetermined period. The period of detecting may be programmable and may be determined by real time clock, processor or instruction cycles. Multiple event types may be selected from for detection and input to a single counter, or alternatively multiple event counters may be provided for various event types. The saturating counter may additionally be periodically reset in a selected operating mode, in combination with the decrementing action performed on the counter.