Abstract: Techniques and mechanisms for circuitry of a processor to determine a count of prefetch instructions which have been retired, or are designated for retirement. In an embodiment, a performance monitoring unit (PMU) monitors the execution of an instruction sequence by a core of said processor. The PMU detects the retirement of a first instruction, and further makes a first determination that the instruction is of a prefetch instruction type. Based on the first determination, counter circuitry of the processor updates a count of one or more instruction retirements, wherein each such retired instruction is of the prefetch instruction type. The PMU further makes a second determination that another retired second instruction is of a non-prefetch instruction type. In another embodiment, the counter circuitry prevents any updating of that same count based on the second determination.