FlashThink: An Early Exit Method For Efficient Reasoning

TL;DR

FlashThink is an early exit method for LLM reasoning that significantly reduces reasoning length by identifying when the model can stop without losing accuracy, thus improving efficiency.

Contribution

We propose a verification model that detects the optimal stopping point in LLM reasoning, enabling early exit and reducing computational overhead.

Findings

Reasoning content reduced by over 77% without accuracy loss.

Effective across multiple benchmarks and models.

Enhances reasoning efficiency in large language models.

Abstract

Large Language Models (LLMs) have shown impressive performance in reasoning tasks. However, LLMs tend to generate excessively long reasoning content, leading to significant computational overhead. Our observations indicate that even on simple problems, LLMs tend to produce unnecessarily lengthy reasoning content, which is against intuitive expectations. Preliminary experiments show that at a certain point during the generation process, the model is already capable of producing the correct solution without completing the full reasoning content. Therefore, we consider that the reasoning process of the model can be exited early to achieve the purpose of efficient reasoning. We introduce a verification model that identifies the exact moment when the model can stop reasoning and still provide the correct answer. Comprehensive experiments on four different benchmarks demonstrate that our proposed method, FlashThink, effectively shortens the reasoning content while preserving the model accuracy. For the Deepseek-R1 and QwQ-32B models, we reduced the length of reasoning content by 77.04% and 77.47%, respectively, without reducing the accuracy.