A four-parameter analytical law predicts LLM inference energy across architectures, revealing quadratic prefill costs, GQA savings, and super-linear growth from reasoning budgets and agentic serving.
Generative AI is billed per token, yet tokens are not equally expensive. Each token enters the KV-cache and raises the cost of those that follow, so energy grows non-linearly along a sequence whose tokens look identical. No analytical model states what a token costs, and the most accurate SOTA model is a fit, not a law: it absorbs architecture into fitted coefficients, requiring per-LLM fitting. We derive closed-form expressions of the computational and memory-access complexity of LLM inference in terms of architectural hyperparameters, covering MHA and GQA, and compare a family of analytical models of increasing granularity. From these, we obtain the SIMPLE Inference Model to Predict LLMs…
KV-cacheMHAGQALLM inferenceprefilldecodeSIMPLE lawenergy complexitygroup-query attentionmulti-head attention
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- Nov 2, 2026
Summary and abstract excerpt via Hugging Face Papers ↗ · arXiv.