1. An apparatus comprising: a data processor; two or more hardware monitors to measure parameters associated with the data processor; a power supply to provide power to the data processor and the hardware monitors; and a controller to control the power supply to adjust an output voltage level of the power supply according to measurements from the hardware monitors, in which different weight values are applied to the hardware monitors under different conditions, and the power supply output voltage level is controlled according to weighted measurements or values derived from the weighted measurements, wherein the controller samples different hardware monitors by different sampling rates, and obtains sampling results as the measurements from the different hardware monitors, and wherein the controller determines a difference between the measurement from each hardware monitor and a corresponding preset value, and samples the hardware monitor more frequently if the difference is equal to or less than a threshold, and samples the hardware monitor less frequently if the difference is greater than the threshold.