English

EAGLE: Speculative Sampling Requires Rethinking Feature Uncertainty

Machine Learning 2025-03-05 v3 Computation and Language

Abstract

Autoregressive decoding makes the inference of Large Language Models (LLMs) time-consuming. In this paper, we reconsider speculative sampling and derive two key observations. Firstly, autoregression at the feature (second-to-top-layer) level is more straightforward than at the token level. Secondly, the inherent uncertainty in feature (second-to-top-layer) level autoregression constrains its performance. Based on these insights, we introduce EAGLE (Extrapolation Algorithm for Greater Language-model Efficiency), a simple yet highly efficient speculative sampling framework. By incorporating a token sequence advanced by one time step, EAGLE effectively resolves the uncertainty, enabling precise second-to-top-layer feature prediction with minimal overhead. We conducted comprehensive evaluations of EAGLE, including all models from the Vicuna and LLaMA2-Chat series, the MoE model Mixtral 8x7B Instruct, and tasks in dialogue, code generation, mathematical reasoning, and instruction following. For LLaMA2-Chat 70B, EAGLE achieved a latency speedup ratio of 2.7x-3.5x, doubled throughput, while maintaining the distribution of the generated text.

Keywords

Cite

@article{arxiv.2401.15077,
  title  = {EAGLE: Speculative Sampling Requires Rethinking Feature Uncertainty},
  author = {Yuhui Li and Fangyun Wei and Chao Zhang and Hongyang Zhang},
  journal= {arXiv preprint arXiv:2401.15077},
  year   = {2025}
}
R2 v1 2026-06-28T14:28:29.972Z