Act Only When It Pays: Efficient Reinforcement Learning for LLM Reasoning via Selective Rollouts

Fuente: arXiv
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Main Authors: Zheng, Haizhong, Zhou, Yang, Bartoldson, Brian R., Kailkhura, Bhavya, Lai, Fan, Zhao, Jiawei, Chen, Beidi
Format: Preprint
Published: 2025
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author Zheng, Haizhong
Zhou, Yang
Bartoldson, Brian R.
Kailkhura, Bhavya
Lai, Fan
Zhao, Jiawei
Chen, Beidi
author_facet Zheng, Haizhong
Zhou, Yang
Bartoldson, Brian R.
Kailkhura, Bhavya
Lai, Fan
Zhao, Jiawei
Chen, Beidi
contents Reinforcement learning, such as PPO and GRPO, has powered recent breakthroughs in LLM reasoning. Scaling rollout to sample more prompts enables models to selectively use higher-quality data for training, which can stabilize RL training and improve model performance. However, this comes at the cost of significant computational overhead. In this paper, we show that a substantial portion of this overhead can be avoided by skipping uninformative prompts before rollout. Our analysis of reward dynamics reveals a strong temporal consistency in prompt value: prompts that are uninformative in one epoch of training are likely to remain uninformative in future epochs. Based on these insights, we propose GRESO (GRPO with Efficient Selective Rollout), an online, lightweight pre-rollout filtering algorithm that predicts and skips uninformative prompts using reward training dynamics. By evaluating GRESO on a broad range of math reasoning benchmarks and models, such as Qwen2.5-Math-1.5B, DeepSeek-R1-Distill-Qwen-1.5B, and Qwen2.5-Math-7B, we show that GRESO achieves up to 2.4x wall-clock time speedup in rollout and up to 2.0x speedup in total training time without accuracy degradation.
format Preprint
id arxiv_https___arxiv_org_abs_2506_02177
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Act Only When It Pays: Efficient Reinforcement Learning for LLM Reasoning via Selective Rollouts
Zheng, Haizhong
Zhou, Yang
Bartoldson, Brian R.
Kailkhura, Bhavya
Lai, Fan
Zhao, Jiawei
Chen, Beidi
Artificial Intelligence
Machine Learning
Reinforcement learning, such as PPO and GRPO, has powered recent breakthroughs in LLM reasoning. Scaling rollout to sample more prompts enables models to selectively use higher-quality data for training, which can stabilize RL training and improve model performance. However, this comes at the cost of significant computational overhead. In this paper, we show that a substantial portion of this overhead can be avoided by skipping uninformative prompts before rollout. Our analysis of reward dynamics reveals a strong temporal consistency in prompt value: prompts that are uninformative in one epoch of training are likely to remain uninformative in future epochs. Based on these insights, we propose GRESO (GRPO with Efficient Selective Rollout), an online, lightweight pre-rollout filtering algorithm that predicts and skips uninformative prompts using reward training dynamics. By evaluating GRESO on a broad range of math reasoning benchmarks and models, such as Qwen2.5-Math-1.5B, DeepSeek-R1-Distill-Qwen-1.5B, and Qwen2.5-Math-7B, we show that GRESO achieves up to 2.4x wall-clock time speedup in rollout and up to 2.0x speedup in total training time without accuracy degradation.
title Act Only When It Pays: Efficient Reinforcement Learning for LLM Reasoning via Selective Rollouts
topic Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2506.02177