Large Language Models (LLMs) have rapidly advanced in recent years, scaling up in both parameter count and context length. However, as context windows extend from thousands to hundreds of thousands of tokens, attention computation becomes the dominant source of memory usage and runtime in decoding stages, severely limiting the efficiency and scalability of long-context LLMs. Sparse attention has emerged as a promising solution, reducing complexity by computing attention over only a subset of context tokens. However, the sparse attention for Multi-head Latent Attention(MLA) which is a variant of standard MHA is rarely studied. In this paper, we introduce RoPE-based Blockwise Sparse Attention (RoBSA), a method designed specifically for MLA during the decoding stage of model inference. RoBSA leverages the decoupled nature of RoPE within MLA to implement token selection in a blockwise manner. RoBSA is a lightweight, training-free, and layer-aware algorithm that can be integrated in a plug-and-play fashion. Our method significantly reduces end-to-end inference latency in the decoding stage by up to 2.55x with minimal accuracy loss compared to full attention in long-context scenarios for very large models.

In knowledge-intensive domains like scientific research, effective decisions rely on organizing and retrieving intricate data. Knowledge graphs (KGs) help by structuring entities, relations, and contextual dependencies, but building KGs in such domains is challenging due to inherent complexity, manual effort, and rapid evolution. Inspired by how humans organize knowledge hierarchically, we propose Tree-KG, an expandable framework that combines structured domain texts with advanced semantic techniques. First, Tree-KG builds a tree-like graph from textbook structures using large language models (LLMs) and domain-specific entities, creating an explicit KG. Then, through iterative expansion with flexible, predefined operators, it uncovers hidden KG while preserving semantic coherence. Experiments demonstrate that Tree-KG consistently surpasses competing methods, achieving the highest F1 scores (12–16% above the second-best), with notable performance (F1 0.81) on the Text-Annotated dataset, highlighting its effectiveness in extracting high-quality information from source texts. Additionally, Tree-KG provides superior structural alignment, domain-specific extraction, and cost-efficiency, delivering robust results with reduced token usage and adaptable, resource-conscious deployment.