A method of controlling a powertrain system includes determining a torque request; selecting feasible input torque and input speed operating points; calculating aggregate system power losses; determining turbo efficiency as a function of a difference between a feasible input torque rate of change and a desired input torque rate of change required to reach the desired output torque; summing the turbo efficiency to the aggregate system power losses to determine total system losses corresponding to feasible input torques and input speed capable of producing the desired output torque; determining a feasible input torque and input speed corresponding to a substantially minimum total system power loss; and selecting as a desired input speed and input torque that corresponds to the substantially minimum total system power loss.