Data-centric training has emerged as a promising direction for improving large language models (LLMs) by optimizing not only model parameters but also the selection, composition, and weighting of training data during optimization. However, existing approaches to data selection, data mixture optimization, and data reweighting are often developed in isolated codebases with inconsistent interfaces, hindering reproducibility, fair comparison, and practical integration. In this paper, we present DataFlex, a unified data-centric dynamic training framework built upon LLaMA-Factory. DataFlex supports three major paradigms of dynamic data optimization: sample selection, domain mixture adjustment, and sample reweighting, while remaining fully compatible with the original training workflow. It provides extensible trainer abstractions and modular components, enabling a drop-in replacement for standard LLM training, and unifies key model-dependent operations such as embedding extraction, inference, and gradient computation, with support for large-scale settings including DeepSpeed ZeRO-3. We conduct comprehensive experiments across multiple data-centric methods. Dynamic data selection consistently outperforms static full-data training on MMLU across both Mistral-7B and Llama-3.2-3B. For data mixture, DoReMi and ODM improve both MMLU accuracy and corpus-level perplexity over default proportions when pretraining Qwen2.5-1.5B on SlimPajama at 6B and 30B token scales. DataFlex also achieves consistent runtime improvements over original implementations. These results demonstrate that DataFlex provides an effective, efficient, and reproducible infrastructure for data-centric dynamic training of LLMs.
A Survey on Efficient Large Language Model Training: From Data-centric Perspectives
State Key Laboratory for Multimedia Information Processing, School of Computer Science, PKU-Anker LLM Lab, Peking University(信息处理国家重点实验室,计算机学院,PKU-Anker LLM实验室,北京大学);University of California, Los Angeles(加州大学洛杉矶分校);University of Washington(华盛顿大学);Georgia Institute of Technology(佐治亚理工学院);Nanyang Technological University(南洋理工大学);HKUST(香港科技大学);University of International Business and Economics(国际商务经济大学)
MedAgentGym: A Scalable Agentic Training Environment for Code-Centric Reasoning in Biomedical Data Science
Emory University(埃默里大学);Georgia Institute of Technology(佐治亚理工学院);University of Illinois Urbana-Champaign(伊利诺伊大学厄巴纳-香槟分校);Yale University(耶鲁大学);UT Southwestern Medical Center(德克萨斯大学西南医学中心);University of Washington(华盛顿大学)
When the Strongest Teacher Is Not the Best Teacher: Student-Centric Answer Selection
University of Washington(华盛顿大学);University of Texas at Austin(德克萨斯大学奥斯汀分校);University of Southern California(南加州大学);Independent Researcher(独立研究者);National University of Singapore(新加坡国立大学);Microsoft(微软);Google(谷歌);Mohamed bin Zayed University of Artificial Intelligence(穆罕默德·本·扎耶德人工智能大学);Northwestern University(西北大学);Allen Institute for AI (AI2)(人工智能研究院(AI2))
EAU: Environment-Agent-User Co-evolution for Training User-Centric Agents
University of Alberta(阿尔伯塔大学);National University of Singapore(新加坡国立大学);Kuaishou Technology(快手科技);Alberta Machine Intelligence Institute (Amii)(阿尔伯塔机器智能研究所)
OpenThaiGPT 1.6 and R1: Thai-Centric Open Source and Reasoning Large Language Models
Mahidol University(玛希隆大学);iApp Technology Co., Ltd.(iApp科技有限公司);Intelligent Informatics and Service Innovation Research Center(智能信息与服务创新研究中心);Artificial Intelligence Entrepreneur Association of Thailand (AIEAT)(泰国人工智能企业家协会(AIEAT))
Order Doesn't Matter, But Reasoning Does: Training LLMs with Order-Centric Augmentation
Shanghai Key Laboratory of Data Science, School of Computer Science, Fudan University(上海数据科学关键实验室,计算机科学学院,复旦大学);School of Data Science, Fudan University(数据科学学院,复旦大学);Ant Group(蚂蚁集团)
SongSage: A Large Musical Language Model with Lyric Generative Pre-training
School of Computer Science, Wuhan University(武汉大学计算机学院);School of Information Management, Wuhan University(武汉大学信息管理学院);Tsinghua University(清华大学);School of Artificial Intelligence, Wuhan University(武汉大学人工智能学院)
From Coarse to Fine: Benchmarking and Reward Modeling for Writing-Centric Generation Tasks
Shanghai Key Laboratory of Data Science, College of Computer Science and Artificial Intelligence, Fudan University(数据科学上海重点实验室,计算机科学与人工智能学院,复旦大学);Shanghai Artificial Intelligence Laboratory(上海人工智能实验室)
AutoDataBench: A Data-centric Testbed for Accelerating Auto Research
The Hong Kong Polytechnic University(香港理工大学);IQuest Research;Shanghai Jiaotong University(上海交通大学);TU Darmstadt(达姆施塔特工业大学);The University of Manchester(曼彻斯特大学);University of Macau(澳门大学);Shanghai University of Finance and Economics(上海财经大学);Beihang University(北京航空航天大学)
Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences(中国科学院深圳先进技术研究院);OpenGVLab, Shanghai AI Laboratory(上海人工智能实验室 OpenGVLab);The University of Hong Kong(香港大学);Nanjing University(南京大学)
Why Does RL Generalize Better Than SFT? A Data-Centric Perspective on VLM Post-Training
College of Computer Science, Sichuan University(四川大学计算机科学学院);Department of Computer Science and Technology, Tsinghua University(清华大学计算机科学与技术系);College of Computer Science and Technology, Zhejiang University(浙江大学计算机科学与技术学院)
Multimodal-Guided Dynamic Dataset Pruning for Robust and Efficient Data-Centric Learning
National Key Laboratory for Novel Software Technology, Nanjing University(新型软件技术国家重点实验室,南京大学);Shanghai Artificial Intelligence Laboratory(上海人工智能实验室);The Chinese University of Hong Kong(香港中文大学)
Memorization Control in Diffusion Models from Denoising-centric Perspective
Department of Computer Science(计算机科学系);Brunel University of London(布鲁内尔大学);Hanoi University of Science and Technology(河内科学技术大学);Faculty of Electrical and Electronic Engineering School of Engineering(电气电子工程系工程学院);Phenikaa University(Phenikaa大学);Greenwich Vietnam FPT University(格林威治越南FPT大学);College of Engineering(工程学院);Shibaura Institute of Technology(Shibaura技术学院)
Data-Centric Machine Learning in Quantum Information Science
University of Illinois Chicago(伊利诺伊大学芝加哥分校);Oak Ridge National Laboratory(橡树岭国家实验室);Tulane University(杜兰大学);DEVCOM US Army Research Laboratory(DEVCOM美国陆军研究实验室)