1. A method of managing power in a parallel computer, the parallel computer comprising a power supply and a plurality of compute nodes, each compute node comprising a computer processor and computer memory operatively coupled to the computer processor, the plurality of compute nodes powered by the power supply through a plurality of direct current to direct current (‘DC-DC’) converters, each DC-DC converter supplying current to an assigned group of compute nodes, each DC-DC converter having a current sensor, the method comprising: monitoring, by the current sensor in each DC-DC converter, an amount of current supplied by that DC-DC converter to its assigned group of compute nodes; determining, by at least one DC-DC converter, that the amount of current supplied to its assigned group of compute nodes is greater than a predefined threshold value; sending, by the at least one DC-DC converter to the plurality of compute nodes in response to the determination that the amount of current supplied to its assigned group of compute nodes is greater than the predetermined threshold value, a global interrupt, including notifying the plurality of compute nodes to reduce power consumption; and responsive to the notification to reduce power consumption, reducing, by the plurality of compute nodes in accordance with power consumption ratios, power consumption of the compute nodes, the power consumption ratios including a computer processor power consumption ratio and a computer memory power consumption ratio.