ML: Kv cache

Machine-learning ideas tagged Kv cache in the ML taxonomy of the Math2NN corpus.

△ Mechanism confirmed, baseline not beaten 2026

Rate-adaptive KV-cache quantizer

Allocate different entropy budgets to different KV-cache blocks instead of assigning every token and head the same nominal bitwidth. Use the ECASQ Lagrangian so high-variance or attention-sensitive blocks receive more codepoints, while predictable blocks collapse to fewer symbols and become highly compressible. Preserve unbiasedness per scalar or block so reconstructed keys and values have zero mean quantization error conditional on the original tensor.

Useful8/10
Difficulty6/10
Novelty7/10
Paper: Entropy-Constrained Adaptive Stochastic Quantization arXiv:2608.18147
△ Mechanism confirmed, baseline not beaten 2026

Entropy-constrained unbiased block quantization

Replace fixed-grid stochastic quantization of each tensor block with an adaptive ordered codebook selected under both an entropy budget and a maximum number of codepoints. Within every interval between adjacent codepoints, use unbiased stochastic interpolation, so the quantized block remains unbiased while the emitted symbol distribution becomes easier for arithmetic or Huffman coding to compress. The representation should reduce actual compressed bytes at fixed MSE, or reduce MSE at fixed…

Useful8/10
Difficulty6/10
Novelty6/10
Paper: Entropy-Constrained Adaptive Stochastic Quantization arXiv:2608.18147
✗ Failed on benchmark 2026

Equal-Volume KV Vector Quantization

Replace consecutive or randomly assigned transformed KV coefficients with groups whose variance-volume is approximately equal. Train one equal-size vector-quantizer codebook per group, so a fixed-width cache does not waste its low-rate budget by forcing high-variance and low-variance coordinates into badly mismatched groups. This is a drop-in quantization-layout change that can be applied to keys, values, or both.

Useful8/10
Difficulty5/10
Novelty7/10
Paper: Spend Bits Where Queries Look: KV Cache Vector Quantization with Attention-Preserving Transforms arXiv:2608.04074
△ Mechanism confirmed, baseline not beaten 2026

Joint Tucker-rank and residual-bit KV allocator

Compress each layer's KV tensor with a partial Tucker approximation over token and feature axes, then encode the truncation residual with a rotated uniform quantizer. Select token rank, feature rank, and residual bit-width jointly under a global byte budget, allowing values with flat spectra to receive residual bits while keys may receive more low-rank capacity.

Useful8/10
Difficulty6/10
Novelty6/10
Paper: A JoLT for the KV cache: Near-lossless KV cache compression via joint Lagrangian allocation of Tucker ranks and a rotated residual for llms arXiv:2607.12550
△ Mechanism confirmed, baseline not beaten 2026

DP-Means Distinct-Item Memory

Replace token-by-token KV storage after an SSM or recurrent encoder with an online allocate-on-novelty cache. A new slot is created only when the incoming key is sufficiently dissimilar from every stored key; otherwise the incoming value is merged into its nearest slot, so repeated or redundant content does not grow the cache.

Useful8/10
Difficulty4/10
Novelty6/10
Paper: Remembering Distinct Items, Not Tokens: A Learnable Dirichlet-Process Cache Between State-Space Models and Attention arXiv:2607.09889
△ Mechanism confirmed, baseline not beaten 2026

Residual-Pivoted Kernel Attention

Replace full PSD self-attention with a pivoted Cholesky/Nyström approximation whose landmarks are sampled from the unexplained diagonal mass. Tokens with large residual self-similarity are more likely to become landmarks, so the rank budget is spent on difficult regions rather than uniformly selected tokens.

Useful7/10
Difficulty5/10
Novelty5/10
Paper: A new analysis of the randomly pivoted Cholesky algorithm arXiv:2608.20633
△ Mechanism confirmed, baseline not beaten 2026

Orthogonally mixed 3-bit KV cache

Replace ordinary per-channel or per-token KV quantization with a structured orthogonal transform followed by blockwise 3-bit quantization. Use a normalized Walsh-Hadamard transform and small SO(4) rotations to spread outliers across coordinates, quantize the transformed vectors, and exploit orthogonality to rotate queries and attention outputs so unquantized attention remains mathematically equivalent.

Useful7/10
Difficulty6/10
Novelty6/10
Paper: RotaryQuant: Fitting 120B MoE Models on Consumer Hardware via Fused Compressed-Space Attention arXiv:2608.08081
△ Mechanism confirmed, baseline not beaten 2026

Lipschitz-Certified Cache Refresh

Attach a certificate to a cached transformer KV state or recurrent latent state and refresh it only while its predicted certificate remains inside a latency-contracted admissible region. The controller uses a bound on certificate drift to guarantee that the state will remain admissible throughout the next sampling, communication, and execution delay, reducing unnecessary recomputation while exposing a measurable refresh boundary.

Useful7/10
Difficulty5/10
Novelty8/10
Paper: CIPS: Maximal Certified Persistence in Cyber-Physical Systems arXiv:2608.06626
✗ Failed on benchmark 2026

Fairness-Budgeted Short-Job Insertion

Replace unrestricted continuous batching with a fairness-constrained scheduler that only inserts a waiting request when its predicted decode footprint remains within a normalized distance of the longest request already in the batch. The fairness budget should be tuned away from the mathematically worst midpoint and validated against real arrival distributions, with the goal of reducing wasted max-driven decode work without falling back to inefficient one-request-at-a-time serving.

Useful7/10
Difficulty4/10
Novelty6/10
Paper: Efficiency and Cost Alignment in Batched LLM Serving via Resource-Fair Scheduling arXiv:2608.02244
△ Mechanism confirmed, baseline not beaten 2026

Residual-energy cross attention

Replace dense query-key attention with an adaptive cross approximation constructed from selected query and key pivot tokens. At each rank, choose the pivot pair that removes large estimated residual energy, update the residual by a rank-1 cross correction, and stop when the residual estimate reaches a target tolerance. The resulting factorization computes approximate attention using a small number of landmark interactions while adapting to the actual token distribution.

Useful7/10
Difficulty6/10
Novelty5/10
Paper: Continuous Cross Approximation of Matrices Arising Out of Kernel Functions arXiv:2607.12540
Unverified 2026

Residual-pivoted landmark attention

Replace uniform or random landmark selection in low-rank attention with approximate greedy pivoted QR selection on the attention matrix. At each step, select the key whose residual attention column has the largest norm, orthogonalize it against previously selected columns, and stop when the residual energy falls below a target tolerance. Use the selected columns as an adaptive attention basis and reconstruct the full attention output through a small coefficient matrix.

Useful6/10
Difficulty6/10
Novelty5/10
Paper: Convergence rates for pivoted QR and LU arXiv:2607.26863
Audited (legacy) 2026

Entropy-Budgeted Contiguous KV Pooling

Use the attention probability distribution over an ordered context to choose contiguous token groups whose pooled attention masses have entropy as close as possible to a prescribed upper budget R. Replace the corresponding key/value vectors by one weighted representative per group, preserving token order and reducing the KV-cache length from n to m. Unlike unconstrained token merging, the entropy constraint gives a direct control knob over how concentrated or diffuse the retained attention…

Useful6/10
Difficulty5/10
Novelty7/10
Paper: Constrained Maximum Entropy Contiguous Aggregations arXiv:2608.25533
Unverified 2026

Global-Shift Randomized Batching

Sample one batching aggressiveness parameter once per serving epoch and use it for all busy periods, instead of independently randomizing every batch. This globally coupled randomness preserves nested batching behavior while preventing a fixed traffic pattern from repeatedly aligning with a deterministic timeout.

Useful5/10
Difficulty3/10
Novelty7/10
Paper: Online Multi-Level Aggregation with Per-Batch Maximum Delay arXiv:2608.06796