EnergyLens: Predictive Energy-Aware Exploration for Multi-GPU LLM Inference Optimization

TL;DR

EnergyLens is a comprehensive framework that predicts and optimizes energy consumption for multi-GPU large language model inference, aiding practitioners in efficient deployment decisions.

Contribution

It introduces an intuitive interface and models for accurately predicting multi-GPU energy behavior, enabling energy-aware optimization without exhaustive profiling.

Findings

Achieves MAPEs between 9.25% and 13.19% for energy prediction.

Reveals up to 1.47x and 52.9x energy variation across configurations.

Identifies Pareto-optimal overlap configurations for compute-communication overlap.

Abstract

We present EnergyLens, an end-to-end framework for energy-aware large language model (LLM) inference optimization. As LLMs scale, predicting and reducing their energy footprint has become critical for sustainability and datacenter operations, yet existing approaches either require production-level code and expensive profiling or fail to accurately capture multi-GPU energy behavior. As a result, practitioners lack tools for deciding which optimizations to prioritize and for selecting among existing deployment configurations when exhaustive profiling is impractical. EnergyLens addresses this gap with an intuitive einsum-based interface that captures LLM specifications including fusion, parallelism, and compute-communication overlap, combined with load-imbalance-aware MoE modeling and an empirically driven communication energy model for multi-GPU settings. We validate EnergyLens on Llama3 and Qwen3-MoE across tensor-parallel and expert-parallel configurations, achieving mean absolute percentage errors (MAPEs) between 9.25% and 13.19% for multi-GPU prefill and decode energy, and 12.97% across SM allocations for Megatron-style overlap. Our energy-driven exploration reveals up to 1.47x and 52.9x energy variation across configurations in prefill and decode efficiency and motivates distributed serving. We further show that compute-communication overlap is difficult to optimize with intuition alone, but EnergyLens correctly identifies Pareto-optimal overlap configurations.