Self-Indexing KVCache: Predicting Sparse Attention from Compressed Keys

Fuente: arXiv
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Main Authors: Yang, Xu, Zhang, Jiapeng, Zhao, Dongyang, Chen, Guo, Tang, Zhuo
Format: Preprint
Published: 2026
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author Yang, Xu
Zhang, Jiapeng
Zhao, Dongyang
Chen, Guo
Tang, Zhuo
author_facet Yang, Xu
Zhang, Jiapeng
Zhao, Dongyang
Chen, Guo
Tang, Zhuo
contents The KV cache in self-attention has emerged as a major bottleneck in long-context and large-batch inference for LLMs. Existing approaches often treat sparsity prediction and compression as separate modules, relying on auxiliary index structures to select relevant tokens, and on complex quantization schemes to reduce memory usage. This fragmented design introduces redundant overhead and limits scalability. In this paper, we propose a novel paradigm: treating the compressed key representation not merely as storage, but as a self-indexing structure that directly enables efficient sparse attention. By designing a sign-based 1-bit vector quantization (VQ) scheme, our method unifies compression and retrieval in a single, hardware-friendly format. This approach eliminates the need for external indices or learning-based predictors, offering a lightweight yet robust solution for memory-constrained inference. All components are designed to be hardware-efficient and easy to implement. By implementing custom CUDA kernels, our method integrates seamlessly with FlashAttention, minimizing additional runtime and memory overhead. Experimental results demonstrate that our approach delivers both effectiveness and efficiency.
format Preprint
id arxiv_https___arxiv_org_abs_2603_14224
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Self-Indexing KVCache: Predicting Sparse Attention from Compressed Keys
Yang, Xu
Zhang, Jiapeng
Zhao, Dongyang
Chen, Guo
Tang, Zhuo
Machine Learning
Artificial Intelligence
The KV cache in self-attention has emerged as a major bottleneck in long-context and large-batch inference for LLMs. Existing approaches often treat sparsity prediction and compression as separate modules, relying on auxiliary index structures to select relevant tokens, and on complex quantization schemes to reduce memory usage. This fragmented design introduces redundant overhead and limits scalability. In this paper, we propose a novel paradigm: treating the compressed key representation not merely as storage, but as a self-indexing structure that directly enables efficient sparse attention. By designing a sign-based 1-bit vector quantization (VQ) scheme, our method unifies compression and retrieval in a single, hardware-friendly format. This approach eliminates the need for external indices or learning-based predictors, offering a lightweight yet robust solution for memory-constrained inference. All components are designed to be hardware-efficient and easy to implement. By implementing custom CUDA kernels, our method integrates seamlessly with FlashAttention, minimizing additional runtime and memory overhead. Experimental results demonstrate that our approach delivers both effectiveness and efficiency.
title Self-Indexing KVCache: Predicting Sparse Attention from Compressed Keys
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2603.14224