A Digital Twin Framework for Liquid-cooled Supercomputers as Demonstrated at Exascale

TL;DR

This paper introduces ExaDigiT, an open-source digital twin framework for liquid-cooled supercomputers, enabling system simulation, optimization, and virtual prototyping, demonstrated through a case study of the Frontier supercomputer.

Contribution

It presents the first comprehensive digital twin framework for liquid-cooled exascale supercomputers, integrating multiple modules for detailed system analysis and validation.

Findings

Validated with six months of telemetry data from Frontier

Revealed complex transient cooling dynamics and energy loss mechanisms

Enabled virtual testing of system scenarios and optimizations

Abstract

We present ExaDigiT, an open-source framework for developing comprehensive digital twins of liquid-cooled supercomputers. It integrates three main modules: (1) a resource allocator and power simulator, (2) a transient thermo-fluidic cooling model, and (3) an augmented reality model of the supercomputer and central energy plant. The framework enables the study of "what-if" scenarios, system optimizations, and virtual prototyping of future systems. Using Frontier as a case study, we demonstrate the framework's capabilities by replaying six months of system telemetry for systematic verification and validation. Such a comprehensive analysis of a liquid-cooled exascale supercomputer is the first of its kind. ExaDigiT elucidates complex transient cooling system dynamics, runs synthetic or real workloads, and predicts energy losses due to rectification and voltage conversion. Throughout our paper, we present lessons learned to benefit HPC practitioners developing similar digital twins. We envision the digital twin will be a key enabler for sustainable, energy-efficient supercomputing.