1. A method comprising: receiving an indication that an end of an interval has been reached; responsive to receiving the indication of the end of the interval, determining a cycle delta, wherein the cycle delta indicates a difference between an expected performance of a circuit and an actual performance of the circuit; determining whether the cycle delta is less than a minimum cycle delta; and responsive to determining that the cycle delta is less than the minimum cycle delta, indicating that the cycle delta is a new minimum cycle delta, and indicating that a performance state is associated with the new minimum cycle delta.