Freshness-Aware Prioritized Experience Replay for LLM/VLM Reinforcement Learning

Fuente: arXiv
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Main Authors: Ma, Weiyu, Zeng, Yongcheng, Song, Yan, Cui, Xinyu, Zhao, Jian, Liu, Xuhui, Elhoseiny, Mohamed
Format: Preprint
Published: 2026
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author Ma, Weiyu
Zeng, Yongcheng
Song, Yan
Cui, Xinyu
Zhao, Jian
Liu, Xuhui
Elhoseiny, Mohamed
author_facet Ma, Weiyu
Zeng, Yongcheng
Song, Yan
Cui, Xinyu
Zhao, Jian
Liu, Xuhui
Elhoseiny, Mohamed
contents Reinforcement Learning (RL) has achieved impressive success in post-training Large Language Models (LLMs) and Vision-Language Models (VLMs), with on-policy algorithms such as PPO, GRPO, and REINFORCE++ serving as the dominant paradigm. However, these methods discard all collected trajectories after a single gradient update, resulting in poor sample efficiency, particularly wasteful for agentic tasks where multi-turn environment interactions are expensive. While Experience Replay drives sample efficiency in classic RL by allowing agents to reuse past trajectories and prioritize informative ones, directly applying Prioritized Experience Replay (PER) to LLMs fails. The rapid policy evolution of billion-parameter models renders stored priorities stale, causing old high-priority trajectories to dominate sampling long after they have become uninformative. We propose Freshness-Aware PER, which addresses this priority staleness problem by augmenting any PER-based priority with a multiplicative exponential age decay grounded in effective sample size analysis. To the best of our knowledge, Freshness-Aware PER is the first work to successfully apply PER to LLM/VLM reinforcement learning. We evaluate on eight multi-step agentic, reasoning, and math competition tasks with 0.5B, 3B, and 7B models. Freshness-Aware PER significantly outperforms on-policy baselines, achieving +46% on NQ Search, +367% on Sokoban, and +133% on VLM FrozenLake, while standard PER without age decay consistently degrades performance. Our code is publicly available at https://github.com/Vision-CAIR/Freshness-Aware-PER.
format Preprint
id arxiv_https___arxiv_org_abs_2604_16918
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Freshness-Aware Prioritized Experience Replay for LLM/VLM Reinforcement Learning
Ma, Weiyu
Zeng, Yongcheng
Song, Yan
Cui, Xinyu
Zhao, Jian
Liu, Xuhui
Elhoseiny, Mohamed
Computation and Language
Machine Learning
Reinforcement Learning (RL) has achieved impressive success in post-training Large Language Models (LLMs) and Vision-Language Models (VLMs), with on-policy algorithms such as PPO, GRPO, and REINFORCE++ serving as the dominant paradigm. However, these methods discard all collected trajectories after a single gradient update, resulting in poor sample efficiency, particularly wasteful for agentic tasks where multi-turn environment interactions are expensive. While Experience Replay drives sample efficiency in classic RL by allowing agents to reuse past trajectories and prioritize informative ones, directly applying Prioritized Experience Replay (PER) to LLMs fails. The rapid policy evolution of billion-parameter models renders stored priorities stale, causing old high-priority trajectories to dominate sampling long after they have become uninformative. We propose Freshness-Aware PER, which addresses this priority staleness problem by augmenting any PER-based priority with a multiplicative exponential age decay grounded in effective sample size analysis. To the best of our knowledge, Freshness-Aware PER is the first work to successfully apply PER to LLM/VLM reinforcement learning. We evaluate on eight multi-step agentic, reasoning, and math competition tasks with 0.5B, 3B, and 7B models. Freshness-Aware PER significantly outperforms on-policy baselines, achieving +46% on NQ Search, +367% on Sokoban, and +133% on VLM FrozenLake, while standard PER without age decay consistently degrades performance. Our code is publicly available at https://github.com/Vision-CAIR/Freshness-Aware-PER.
title Freshness-Aware Prioritized Experience Replay for LLM/VLM Reinforcement Learning
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2604.16918