A data processing system includes a plurality of power supply modules each having a comparing unit for comparing an output-current value supplied to a computer with a threshold value, the plurality of power supply modules continue the comparison when the output-current value is equal to or less than the threshold value and outputs an output-current excess signal to a plurality of server blades when the output-current value is equal to or greater than the threshold value, and the plurality of server blades control respectively power consumptions of the server blades to make a power consumption value of the server blades to an equal to or less than a predetermined value on a power source non-redundancy.