Protection Is (Nearly) All You Need: Structural Protection Dominates Scoring in Globally Capped KV Eviction

In three linesStudy of KV cache eviction policies (LRU, H2O, SnapKV, StreamingLLM, Ada-KV, QUEST, Random) under global cap. Without structural boundary protection, all collapse to F1≤0.064. Reserving 10% cache at each boundary recovers 69–90% quality on LongBench at C=256 (13% retention). Position-0 holds ~75% attention mass; protecting structurally critical tokens dominates over scoring differences.

Summary generated by Claude — human-verified