arXiv Computation and Language By Utkarsh Kanwat

Folding Attention Biases into Keys Makes Compacted KV Caches Run on Standard Kernels

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The paper introduces a method to incorporate attention bias directly into the keys of compacted KV caches, enabling standard kernels like FlashAttention and vLLM to use these folded caches without modification. By fitting a bias along a closed‑form direction per head, the approach preserves the cache size and head dimension while bounding output error based on query projections. Experiments on Qwen3 and Llama‑3.1 models show that the folded caches match or exceed the accuracy of the original Attention Matching method across various benchmarks, with comparable or lower KL divergence to full caches.

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