arXiv Machine Learning

A Layer-wise Analysis of Supervised Fine-Tuning

The paper investigates how supervised fine‑tuning (SFT) affects different layers of language models, finding that middle layers (20–80%) remain stable while the final layers are highly sensitive to changes. Using information‑theoretic, geometric, and optimization metrics across 1B‑32B models, the authors identify a depth‑dependent pattern and introduce Mid‑Block Efficient Tuning, which updates only the critical intermediate layers. Experiments show this method outperforms standard LoRA by up to 10.2 % on GSM8K (OLMo2‑7B) with lower parameter overhead, suggesting that alignment can be achieved with localized architectural changes.

arXiv Machine Learning
Jun 5

Dominant-Layer ZO: A Single Layer Dominates Zeroth-Order Fine-Tuning of LLMs

arXiv:2606. 05516v1 Announce Type: new Abstract: Zeroth-order (ZO) optimization enables memory-efficient fine-tuning of large language models (LLMs) using only forward passes, but it remains unclear how useful adaptation is distributed across layers.

By Wanhao Yu, Ziyan Wang, Zheng Wang, Abeer Matar Almalky, Yihang Zuo, Shuteng Niu, Sen Lin, Adnan Siraj Rakin, Deliang Fan, Li Yang
arXiv AI
4d ago

Leaner Training, Lower Leakage: Revisiting Memorization in LLM Fine-Tuning with LoRA

The paper investigates how memorization behaves during fine‑tuning of large language models with LoRA, a parameter‑efficient technique. It finds that LoRA fine‑tuning diverges from previous results seen in full fine‑tuning and pre‑training: factors like model size and data duplication no longer predict memorization in the same way. Using a relaxed similarity‑based metric, the authors show that LoRA substantially lowers memorization risk while preserving strong task performance.

By Fei Wang, Baochun Li
arXiv AI
Oct 28

An Embarrassingly Simple Data Selection Strategy for Million-Scale Multi-Modal Instruction-Tuning

The paper introduces SSR, a simple yet effective data selection strategy for million‑scale multi‑modal instruction‑tuning. SSR uses interaction styles as a proxy for structural diversity and decomposes data quality into capability‑specific scores, forming a rich profile for each sample. By casting selection as submodular coverage maximization, SSR consistently outperforms random sampling across two architecture stacks, multiple data pools, and 14 benchmarks, achieving 99.1% of full‑data performance with only 30% of a 2.6M pool.

By Mengyao Lyu, Yan Li, Huasong Zhong, Hui Chen, Jungong Han, Guiguang Ding, Zhenheng Yang
arXiv Machine Learning
Aug 27

Ladder Up, Memory Down: Low-Cost Fine-Tuning With Side Nets

The paper introduces Ladder Side Tuning (LST), a parameter‑efficient fine‑tuning method that adds a lightweight side network to large language models. LST matches QLoRA’s compute scaling while halving peak memory usage, enabling 7B‑parameter models to be fine‑tuned on a single 12 GB GPU with 2k‑token contexts without gradient checkpointing. The authors also present xLadder, a depth‑extended variant that increases effective depth through cross‑connections, allowing deeper reasoning without extra memory overhead.

By Estelle Zheng, Nathan Cerisara, S\'ebastien Warichet, Emmanuel Helbert, Christophe Cerisara