Evaluation of Power Management Control on the Supercomputer Fugaku

The supercomputer Fugaku, which recently ranked number one on multiple supercomputing lists, including the Top500 in June 2020, has various power control features, such as (1) an eco mode that utilizes only one of two floating-point pipelines while decreasing the power supply to the chip; (2) a boost mode that increases clock frequency; and (3) a core retention function that turns unused cores into a low-power state. By orchestrating these power-performance features while considering the characteristics of currently running applications, we can potentially gain even better system-level energy efficiency. In this article, we report on the effectiveness of these features using the pre-evaluation environment for Fugaku. As a result, we confirmed several prominent results useful for the operation of the Fugaku system, including: remarkable power reduction and energy-efficiency improvement by coordinating the eco mode and the core retention feature in the memory intensive case; a 10% speed-up with a 17% power consumption increase using the boost mode in the CPU intensive case; and considerable power variations across over 20K nodes.