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abstract indexed · arXiv 2609.16617 · updated 2026-10-18

Divergence Timing and Cumulative Disagreement under KV-Cache Eviction

First page of Divergence Timing and Cumulative Disagreement under KV-Cache Eviction
From the original paper · arXiv 2609.16617Page 1. Select the image to read the PDF.

This paper does not propose a replacement technique; it provides a measurement framework (coupling-based decomposition and residual-branch conditional Monte Carlo) that quantifies how KV-cache eviction policies such as SnapKV and recent-token retention diverge from full-cache generation. Adopting the analysis itself costs nothing at inference but requires instrumented paired trajectories to estimate divergence timing and exposure, which adds engineering complexity without changing serving performance. What can fail is transferability: the finding that 85-90% of mismatch mass comes from post-divergence exposure is an exploratory result on 288 documents and two 7-8B models, so eviction-policy rankings and window conclusions may not hold for other workloads, models, or retention budgets.

For solo builders

A possible application for this research area. Paper-specific feasibility still needs a full-paper review.

Long customer conversations exhaust memory or limit concurrent requests.

What you would change

Change only the attention cache policy, after checking model and runtime support.

Try the idea on your product

A proposed first test. Set your budget and success criteria before running it.

Change only the attention cache policy, after checking model and runtime support.

Compare against

The same model with its ordinary attention cache.

  1. Locate the paper's implementation and check its license, model support, data needs, and hardware requirements. Stop here if you cannot obtain the required artifacts.
  2. Save a small set of representative product tasks and expected outcomes. Keep evaluation tasks out of any training or tuning, and choose quality and cost limits before running.
  3. Run the baseline and the proposed change on identical inputs. Keep other settings fixed and repeat paired runs to expose variation.
  4. Save per-task outputs, failures, timings, and all usage costs. Review regressions before expanding the test.

What to measure

Peak cache memory, long-context answer quality, first-token latency, and requests completed.

When to keep it

Keep the change only if it meets your preselected quality and latency limits and improves the metric you care about after setup and operating costs. Otherwise retain the baseline. This is an exploration plan, not a validated recommendation.

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published evidence setup
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source-linked claims
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exposure checks
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Why it was shortlisted

The technical change, research area, and reason it entered the archive.

recommendation
watch
research area
KV cache
technical change
Divergence analysis of KV-cache eviction policies
published
2026-09-15

The paper is a diagnostic study rather than an adoptable method, and its comparative evidence on SnapKV retention settings is exploratory and confined to two open models, so it informs but does not yet justify changing a production eviction policy.

Central equations

Original equations, typeset for reading. Paperraft explanations connect the mechanism, its aim, and the evidence.

We make the trajectory comparison precise through recursive overlap–residual maximal coupling [13, 21]. Reference kernels P and intervention kernels Qa generate paired continuations, each with its original marginal law. Their cumulative positional disagreement is

RSMC(a)=𝔼[1H∑t=1H𝟏{Xt≠Yta}].

equation (1) · §1 Introduction · metric

The equality for ΠH follows from the same measurable partition and Equation (3). To separate the available time from the rate of mismatch, let

EH=1H𝔼[∑t=1H𝟏{τ<t}]=1H∑s=1Hps(H−s),CH={ΠH/EH,EH>0,0,EH=0,RSMC=OH+EHCH.

equation (7) · §3 From Divergence Timing to Cumulative Disagreement · proposed method

For every admissible profile on an alphabet with at least two symbols, allowing P,Q to vary over all autoregressive kernels subject to that profile, the compatible risks are exactly

{RSMC​(P,Q):𝒮L​(P,Q)=(p,ρ)}=[RL​(p,ρ),RL​(p,ρ)+BL​(p)].

equation (10) · §3 From Divergence Timing to Cumulative Disagreement · proposed method

equations from arXiv HTML · fetched 2026-10-15

Claims and evidence

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  1. claim 01Paperraft inference
    Read the brief interpretation

    This paper does not propose a replacement technique; it provides a measurement framework (coupling-based decomposition and residual-branch conditional Monte Carlo) that quantifies how KV-cache eviction policies such as SnapKV and recent-token retention diverge from full-cache generation. Adopting the analysis itself costs nothing at inference but requires instrumented paired trajectories to estimate divergence timing and exposure, which adds engineering complexity without changing serving performance. What can fail is transferability: the finding that 85-90% of mismatch mass comes from post-divergence exposure is an exploratory result on 288 documents and two 7-8B models, so eviction-policy rankings and window conclusions may not hold for other workloads, models, or retention budgets.

    This is a Paperraft inference. It is not pinned to a verified PDF passage.

    Inspect the source

Exposure map

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quality

Still unknown

Which tasks improve, and which regress against the baseline?

compute and memory

Still unknown

What memory, hardware, and total compute does the complete method require?

latency

Still unknown

Are startup time, typical response time, and slow requests measured separately?

operations

Still unknown

What must be monitored, maintained, and rolled back?

software compatibility

Still unknown

Does the implementation support your model, runtime, and hardware?

security

Still unknown

What new data access, permissions, or trust boundaries does it introduce?

data and training

Still unknown

What data preparation or training is required, and is it included in the cost?

reproducibility

Still unknown

Are code, versions, inputs, and evaluation scripts available?

Continue the investigation

A reading guide for KV cache.

Editorial prompts, not findings from this paper or a validated test plan. Detailed analysis is still pending for the topics below.

What to inspect

Which tokens or cache entries are retained, compressed, or discarded? Look for tests of lost information.

Plan a fair comparison

Can you keep prompts and decoding settings fixed while measuring cache size, latency, and answer quality?

Questions for adoption

Does the evaluation cover long conversations and questions about information introduced early?

Read the paper with these questions

Inside the paper

Preview the first 3 pages of the original PDF. Click the stack to turn the page.

The downloadable skill includes SKILL.md and evidence.json, with recorded findings and unanswered checks. TRY-IT.md adds a product test plan and a blank results sheet.

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Provisional research brief updated 2026-10-18. Paperraft has not reproduced this experiment.

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