OptPO: Optimal Rollout Allocation for Test-time Policy Optimization

Fuente: arXiv
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Hauptverfasser: Wang, Youkang, Wang, Jian, Chen, Rubing, Zeng, Tianyi, Wei, Xiao-Yong, Li, Qing
Format: Preprint
Veröffentlicht: 2025
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author Wang, Youkang
Wang, Jian
Chen, Rubing
Zeng, Tianyi
Wei, Xiao-Yong
Li, Qing
author_facet Wang, Youkang
Wang, Jian
Chen, Rubing
Zeng, Tianyi
Wei, Xiao-Yong
Li, Qing
contents Test-time policy optimization enables large language models (LLMs) to adapt to distribution shifts by leveraging feedback from self-generated rollouts. However, existing methods rely on fixed-budget majority voting to estimate rewards, incurring substantial computational redundancy. We propose Optimal Rollout Allocation for Test-time Policy Optimization (OptPO), a principled framework that adaptively allocates inference budgets. By formulating the voting process as a Bayesian sequential probability ratio test, OptPO dynamically halts sampling once the posterior confidence in a consensus answer exceeds a specified threshold. Crucially, it utilizes the retained rollouts for on-policy updates, seamlessly integrating with algorithms like PPO or GRPO without requiring ground-truth labels. Across diverse reasoning benchmarks, OptPO significantly reduces rollout overhead compared to fixed-sample baselines while preserving or improving accuracy. By unifying statistically optimal stopping with test-time learning, OptPO offers a computationally efficient paradigm for test-time adaptation. The source code will be open upon acceptance at https://open-upon-acceptance.
format Preprint
id arxiv_https___arxiv_org_abs_2512_02882
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle OptPO: Optimal Rollout Allocation for Test-time Policy Optimization
Wang, Youkang
Wang, Jian
Chen, Rubing
Zeng, Tianyi
Wei, Xiao-Yong
Li, Qing
Machine Learning
Artificial Intelligence
Computation and Language
68T05, 68T50, 68T07
Test-time policy optimization enables large language models (LLMs) to adapt to distribution shifts by leveraging feedback from self-generated rollouts. However, existing methods rely on fixed-budget majority voting to estimate rewards, incurring substantial computational redundancy. We propose Optimal Rollout Allocation for Test-time Policy Optimization (OptPO), a principled framework that adaptively allocates inference budgets. By formulating the voting process as a Bayesian sequential probability ratio test, OptPO dynamically halts sampling once the posterior confidence in a consensus answer exceeds a specified threshold. Crucially, it utilizes the retained rollouts for on-policy updates, seamlessly integrating with algorithms like PPO or GRPO without requiring ground-truth labels. Across diverse reasoning benchmarks, OptPO significantly reduces rollout overhead compared to fixed-sample baselines while preserving or improving accuracy. By unifying statistically optimal stopping with test-time learning, OptPO offers a computationally efficient paradigm for test-time adaptation. The source code will be open upon acceptance at https://open-upon-acceptance.
title OptPO: Optimal Rollout Allocation for Test-time Policy Optimization
topic Machine Learning
Artificial Intelligence
Computation and Language
68T05, 68T50, 68T07
url https://arxiv.org/abs/2512.02882