Fugaku's Power Control Mechanism and Efforts Against the Energy Cost Crisis

One of the development goals of Fugaku was high power efficiency. Fugaku's power consumption is 30 MW when TOP500 is running, and about 20 MW even during normal operation, so it was necessary to reduce energy consumption for continuous operation. Furthermore, in order to respond to the rapid increase in energy costs in recent, it became necessary to suspend some nodes at Fugaku, making energy reduction an urgent task. We will introduce efforts to utilize power modes that appropriately combine the power knobs installed in Fugaku's A64FX processor and their effects. By appropriately selecting the power mode, we reduced the power consumption while suppressing the performance impact on the job, resulting in a reduction in energy. As a result of these effects, we were able to reduce power consumption by approximately 10% during normal operation.