重新审视大语言模型蒸馏:基于约束马尔可夫决策过程的视角
Rethinking Large Language Model Distillation: A Constrained Markov Decision Process Perspective
September 26, 2025
作者: Matthieu Zimmer, Xiaotong Ji, Tu Nguyen, Haitham Bou Ammar
cs.AI
摘要
我们提出了一种新颖的大型语言模型(LLM)蒸馏方法,将其表述为一个约束强化学习问题。尽管近期研究已开始探索将任务特定奖励整合到蒸馏过程中,但现有方法通常依赖于临时性的奖励权重分配。我们提出了一种原则性的优化框架,该框架在最大化任务特定奖励的同时,将教师模型的偏离度约束在指定阈值以下。我们的方法将约束状态增强强化学习适应于蒸馏场景,引入了一种改进的奖励函数,该函数在无需状态增强或部署期间访问教师模型的情况下,仍能保持约束满足的理论保证,并且避免了双重拉格朗日方法的计算开销。通过在数学推理任务上的广泛实验,我们证明了与软拉格朗日松弛基线相比,我们的方法在保持竞争力的任务性能的同时,实现了更好的约束满足率和更优的推理能力。我们的框架为资源受限环境下的奖励感知蒸馏提供了一个理论基础坚实且实际高效的解决方案。
English
We introduce a novel approach to large language model (LLM) distillation by
formulating it as a constrained reinforcement learning problem. While recent
work has begun exploring the integration of task-specific rewards into
distillation processes, existing methods typically rely on ad-hoc reward
weighting. We propose a principled optimization framework that maximizes
task-specific rewards while constraining the divergence from the teacher model
to remain below a specified threshold. Our approach adapts constrained state
augmented reinforcement learning to the distillation setting, introducing a
modified reward function that maintains theoretical guarantees of constraint
satisfaction without requiring state augmentation or teacher model access
during deployment and without the computational overhead of the dual Lagrangian
methods. Through extensive experiments on mathematical reasoning tasks, we
demonstrate that our method achieves better constraint satisfaction rates and
better reasoning compared to the soft Lagrangian relaxation baselines while
maintaining competitive task performance. Our framework provides a
theoretically grounded and practically efficient solution for reward-aware
distillation in resource-constrained settings.