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Main Authors: Xi, Haocheng, Ruan, Charlie, Liao, Peiyuan, Lin, Yujun, Cai, Han, Zhao, Yilong, Yang, Shuo, Keutzer, Kurt, Han, Song, Zhu, Ligeng
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2601.14243
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author Xi, Haocheng
Ruan, Charlie
Liao, Peiyuan
Lin, Yujun
Cai, Han
Zhao, Yilong
Yang, Shuo
Keutzer, Kurt
Han, Song
Zhu, Ligeng
author_facet Xi, Haocheng
Ruan, Charlie
Liao, Peiyuan
Lin, Yujun
Cai, Han
Zhao, Yilong
Yang, Shuo
Keutzer, Kurt
Han, Song
Zhu, Ligeng
contents Reinforcement learning (RL) is essential for enhancing the complex reasoning capabilities of large language models (LLMs). However, existing RL training pipelines are computationally inefficient and resource-intensive, with the rollout phase accounting for over 70% of total training time. Quantized RL training, particularly using FP8 precision, offers a promising approach to mitigating this bottleneck. A commonly adopted strategy applies FP8 precision during rollout while retaining BF16 precision for training. In this work, we present the first comprehensive study of FP8 RL training and demonstrate that the widely used BF16-training + FP8-rollout strategy suffers from severe training instability and catastrophic accuracy collapse under long-horizon rollouts and challenging tasks. Our analysis shows that these failures stem from the off-policy nature of the approach, which introduces substantial numerical mismatch between training and inference. Motivated by these observations, we propose Jet-RL, an FP8 RL training framework that enables robust and stable RL optimization. The key idea is to adopt a unified FP8 precision flow for both training and rollout, thereby minimizing numerical discrepancies and eliminating the need for inefficient inter-step calibration. Extensive experiments validate the effectiveness of Jet-RL: our method achieves up to 33% speedup in the rollout phase, up to 41% speedup in the training phase, and a 16% end-to-end speedup over BF16 training, while maintaining stable convergence across all settings and incurring negligible accuracy degradation.
format Preprint
id arxiv_https___arxiv_org_abs_2601_14243
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Jet-RL: Enabling On-Policy FP8 Reinforcement Learning with Unified Training and Rollout Precision Flow
Xi, Haocheng
Ruan, Charlie
Liao, Peiyuan
Lin, Yujun
Cai, Han
Zhao, Yilong
Yang, Shuo
Keutzer, Kurt
Han, Song
Zhu, Ligeng
Machine Learning
Computation and Language
Reinforcement learning (RL) is essential for enhancing the complex reasoning capabilities of large language models (LLMs). However, existing RL training pipelines are computationally inefficient and resource-intensive, with the rollout phase accounting for over 70% of total training time. Quantized RL training, particularly using FP8 precision, offers a promising approach to mitigating this bottleneck. A commonly adopted strategy applies FP8 precision during rollout while retaining BF16 precision for training. In this work, we present the first comprehensive study of FP8 RL training and demonstrate that the widely used BF16-training + FP8-rollout strategy suffers from severe training instability and catastrophic accuracy collapse under long-horizon rollouts and challenging tasks. Our analysis shows that these failures stem from the off-policy nature of the approach, which introduces substantial numerical mismatch between training and inference. Motivated by these observations, we propose Jet-RL, an FP8 RL training framework that enables robust and stable RL optimization. The key idea is to adopt a unified FP8 precision flow for both training and rollout, thereby minimizing numerical discrepancies and eliminating the need for inefficient inter-step calibration. Extensive experiments validate the effectiveness of Jet-RL: our method achieves up to 33% speedup in the rollout phase, up to 41% speedup in the training phase, and a 16% end-to-end speedup over BF16 training, while maintaining stable convergence across all settings and incurring negligible accuracy degradation.
title Jet-RL: Enabling On-Policy FP8 Reinforcement Learning with Unified Training and Rollout Precision Flow
topic Machine Learning
Computation and Language
url https://arxiv.org/abs/2601.14243