arXiv AI By Jiahao Zheng, Yifan Qin, Xiaobo Sharon Hu, Yiyu Shi

Interface-Aware KV Cache Quantization for Dense On-Chip NVM in Long-Context LLM Decoding

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arXiv AI
6d ago

GAAC: Lossless KV Compression for Bandwidth-Efficient LLM Inference on Personal Devices

The paper introduces GAAC, a lossless key‑value (KV) compression method for large language model inference on personal devices. GAAC encodes BF16 exponents with per‑channel base‑plus‑offset codes, adapts code widths across small groups, and reconstructs KV tiles on the fly to avoid full‑cache decompression. Experiments show 1.4× compression for BF16 KV, speedups of up to 1.27× in decode attention, and a 26% reduction in resident KV memory while boosting throughput on NVIDIA and Apple hardware.

By Yipin Guo, Arun M George, Siddharth Joshi
arXiv Machine Learning
Sep 29

The KV Cache Is the New Memory Wall

The paper argues that for large‑context autoregressive language‑model inference, memory bandwidth—specifically the Key‑Value (KV) cache—becomes the limiting resource rather than arithmetic throughput. It analytically derives how arithmetic intensity decays with context length for NVIDIA H100, NVIDIA B200, and AMD MI300X, identifies crossover points where KV traffic overtakes weight traffic, and evaluates representative techniques across five compression domains. The study finds a three‑regime behavior: below the crossover, weight traffic dominates and KV compression offers little benefit; beyond it, KV traffic dominates and compression methods trade quality for bandwidth, with paging and prefix sharing being lossless but capacity‑limited, while quantization and eviction directly reduce bandwidth at the cost of accuracy. whyItMatters":"The work provides a unified analytical framework and a standardized protocol that enable consistent comparison of KV‑compression techniques across hardware and workloads, guiding practitioners in selecting appropriate methods for long‑context inference."

By Tejinder Singh