norgitov/ trends
Technology · people · ideas
Back to discovery/Daily Papers2 hours ago

Periodic Weak Spots: Phase Sensitivity from Chunked KV-Cache Compression

Chunked KV-cache compression reduces the memory and attention costs of long-context inference by compressing windows of consecutive tokens into fewer cache entries at a fixed stride. Such compression also introduces a new positional coordinate: a token's phase, or its position relative to compression-window boundaries. We uncover a systematic asymmetry in models using such compression: the same information can be easy to retrieve at one phase and difficult at another. We call this periodic variation in retrieval performance phase sensitivity. In large open-weight models with such compression, long-context retrieval accuracy can differ by up to 40 percentage points across phases, revealing periodic weak spots that average benchmark scores can conceal. To investigate this behavior, we pretrain a family of transformers from scratch across multiple KV-compression designs, reproducing phase sensitivity across the variants. Mechanistic analysis using causal interventions in these models reveals phase specialization: different attention components contribute asymmetrically to retrieving information at different source phases. We further analyze idealized retrieval models, showing how gradient flow dynamics may favor sharp phase specialization. Evaluating models with chunked KV-cache compression thus requires measuring across compression phases: high average accuracy can coexist with systematic positional failures.

Translation pending · showing the source description
Open original
SIGNAL FROM THE SOURCE
86
source votes
Tracking sinceSeptember 30, 202686 source votes
Momentum+12.86/hover 3.03 h
Discussion—Read comments ↗
PublishedSeptember 28, 2026Xingyu Zhu, Pu, Yi
BEHIND THE NUMBERS

How interest changes

History starts here

The chart will appear after repeat observations. The current metric comes from the source.

86 source votes

Real observations only. History before source connection is not reconstructed.

A useful discovery?
KEEP EXPLORING

Connected ideas

Explore topic