We present the first systematic study of Massive activations (MAs) in layer-interleaved HLA LLMs and uncover two architecture-aligned morphologies: MAs consistently spike immediately before full attention layers, forming pre-attention spikes (PAS), and can persist through intervening linear attention layers, giving rise to inter-spike plateaus (ISP). As full attention becomes denser, successive PAS become increasingly connected through ISP, ultimately recovering the stable MA morphology of full attention LLMs.
arXiv:2603. 22473v2 Announce Type: replace-cross Abstract: Hybrid language models combine softmax attention with linear-time sequence mechanisms such as state-space or linear-attention layers, but the functional contribution of each component type remains insufficiently characterized.
By Hector Borobia, Elies Segu\'i-Mas, Guillermina Tormo-Carb\'o
The paper identifies a single input embedding channel, called the massive activation gating channel (MAGC), that controls the emergence of massive activations in large language models. When the MAGC value is sufficiently large or small, the spike feed‑forward network outputs exhibit exceptionally large magnitudes. The authors verify MAGC across six models and provide a theoretical explanation linking the channel to a quadratic form that mixes specific columns of the down‑projection matrix, which produce massive activations.
By Minjia Mao, Shi Chen, Bowen Yin, Xiao Fang
arXiv:2610.10114v1 Announce Type: new
Abstract: The architectural design of Large Language Models (LLMs) is shifting from traditional full-attention-only models to hybrid models, which combine differ...
By Xiaoran Liu, Ziwei He, Xipeng Qiu
Fine‑tuning reshapes internal representations of large language models, affecting attention patterns and layer‑wise activations. The study shows that components identified by EAP as important for task performance cluster in specific layers, yet these layers do not align with those undergoing the largest representational changes. Additionally, overlapping EAP components across different tasks do not guarantee cross‑task transfer and can even degrade performance when tasks differ in nature.
By Lingfang Li, Procheta Sen, Shubham Das, Danushka Bollegala
arXiv:2609.39661v1 Announce Type: new
Abstract: Self-attention gives LLMs fine-grained, query-dependent access to context, but dense token interactions incur quadratic prefill cost and a key--value c...
By Zhentao Tan, Jingyi Shen, Yanbo Li, Yao Liu, Yue Wu, Jieping Ye