1. A computer readable medium for executing a set of instructions, the computer readable medium comprising: in an inner loop: establishing estimates of state variables of a substrate planarizing cycle, wherein establishing includes the use of an extended Kalman filter (EKF) engine; and estimating the endpoint of the substrate planarizing cycle based upon the estimates of the state variables; in an outer loop: asynchronously comparing at least one of a state variable and an endpoint to an offline metrology database; and sending and information statement from the outer loop to the inner loop.