Automatic Configuration of LLM Post-Training Pipelines

Channe Chwa, Xinle Wu, Yao Lu


Abstract
LLM post-training pipelines that combine supervised fine-tuning and reinforcement learning are difficult to configure under realistic compute budgets: the configuration space is high-dimensional and heterogeneous, stages are strongly coupled, and each end-to-end evaluation is expensive. We propose AutoPipe, a budget-aware two-phase framework for configuration selection in LLM post-training. Offline, AutoPipe learns a dataset-conditioned learning-to-rank surrogate from historical runs, capturing within-dataset preferences and providing transferable guidance toward promising regions of the configuration space. Online, for a new dataset, AutoPipe uses the offline guidance to steer Bayesian optimization and models dataset-specific deviations with a Gaussian-process residual surrogate. To reduce evaluation cost, each trial is early-stopped and scored by a learned predictor that maps early training signals to a low-cost proxy for final post-training performance. Experiments on biomedical reasoning tasks show that AutoPipe achieves performance comparable to full-fidelity HPO baselines at a fraction of their online cost, while outperforming offline-only approaches and early-stopped HPO variants.
Anthology ID:
2026.emnlp-main.2324
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
52787–52813
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2324/
DOI:
Bibkey:
Cite (ACL):
Channe Chwa, Xinle Wu, and Yao Lu. 2026. Automatic Configuration of LLM Post-Training Pipelines. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 52787–52813, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Automatic Configuration of LLM Post-Training Pipelines (Chwa et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2324.pdf