🤖 AI Summary
This work investigates emergent synchronization among multiple independent AI training tasks operating under a shared power budget, where load-dependent throttling mechanisms—such as power capping, voltage droop, and shared cooling—can induce collective dynamics that cause aggregate power fluctuations to scale linearly rather than decay with the square root of the number of tasks as conventionally expected. By modeling colocated training workloads as a generalized Kuramoto system, the study reveals for the first time that power management mechanisms alone can drive phase locking even in the absence of explicit clock synchronization. Theoretical analysis demonstrates that when phase lags satisfy specific conditions, the effective coupling transitions from repulsive to attractive, leading to a first-order synchronization transition with hysteresis. Building on these insights, the authors propose a phase-scattering scheduling strategy that raises the synchronization threshold, validated through dual-task power-capping experiments aligning closely with theoretical predictions.
📝 Abstract
Large-scale AI training turns computing facilities into multi-megawatt loads whose power draw is periodic: tens of thousands of accelerators step in lockstep between compute-bound phases near peak power and communication-bound phases where they idle. Prior work treats each facility as an exogenous periodic forcing on the grid. We pose the operator's question instead: when many independent training jobs share one oversubscribed power envelope, do their cycles stay independent, so aggregate fluctuation grows as the square root of the number of jobs, or can the power-management stack phase-lock them into linear growth? This is emergent synchronization in a population of nonlinear oscillators - the Kuramoto setting - but classical coupling is absent, since accelerator clocks are decoupled from line frequency. We identify the coupling channel in load-dependent throttling: caps, voltage droop, and shared cooling slow computation exactly when aggregate demand is high. Formalizing the fleet as a generalized Kuramoto system, we obtain three operator-facing statements. Dimension: the coupling is repulsive to leading order and turns attractive only when the control loop's phase lag exceeds half a cycle; protection is mode-selective, so rate diversity is required. Detect: frequency-correlated frustration makes the onset first-order and hysteretic. Mitigate: phase-scattering scheduling raises every mode threshold at once. The prediction is falsifiable by a two-job co-capped measurement, which we specify.