A computer-implemented method enables global throttling of processing nodes in a rack-configured information handling system (RIHS). A rack-level management controller receives power-usage data and operating parameters associated with processing nodes within separately-controlled blocks of the RIHS. A power subsystem of the RIHS regulates an amount of power supplied to the processing nodes of the RIHS based on the power-usage data and operating parameters for the processing nodes and a total amount of available power for distribution within the RIHS. In response to detecting a condition that reduces the total amount of available power for distribution within the IHS, the management controller autonomously initiates global throttling of the processing nodes within the IHS to reduce power consumption by at least one of the processing nodes. The global throttling is completed via a signal transfer over a select Ethernet cable wire to connected block controllers that control the processing nodes.