ResearchResearch paperEfficiency & Inference1 source · Oct 9, 2026

ReplaySSM: Cache SSM Inputs, Not State

We introduce ReplaySSM, which unrolls the recurrence to represent the state as a checkpoint and a buffer of recent SSM inputs.

Key points

  • State-space models (SSMs) maintain a fixed-size recurrent state, but reading and writing it at every decoding step can bottleneck hybrid models.
  • This eager state management causes large state I/O with low arithmetic intensity, leaves speculative decoding no cheap rollback, and feeds state quantization error into subsequent recurrent updates.
  • Keeping recent inputs also makes speculative rollback a buffer-pointer operation and enables output-only verification without materializing intermediate states.
  • We implement ReplaySSM in vLLM for Mamba-2 and Gated DeltaNet.

Sources (1)

  • [1]ReplaySSM: Cache SSM Inputs, Not State
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 9, 03:59 PM
    We introduce ReplaySSM, which unrolls the recurrence to represent the state as a checkpoint and a buffer of recent SSM inputs.
    State-space models (SSMs) maintain a fixed-size recurrent state, but reading and writing it at every decoding step can bottleneck hybrid models.

Extractive summary: sentences quoted from the sources.

Before this

  1. Oct 9, 2026CNN-Transformer with Sigmoid Label for High-Resolution Sub-Degree DOA Estimation
  2. Oct 9, 2026Surfing the Activation Wave: Analyzing the Information and Geometry of LLM Hidden States for Speculative Decoding
  3. Oct 8, 2026mistralai/Voxtral-Mini-4B-Realtime-Arabic
  4. Oct 8, 2026Deflating the Hessian: Rank-4 W4A4 Quantization for Multimodal Diffusion Transformers
  5. Oct 8, 2026ConwayResearch/Underdog-Saluki-27B-1.0
  6. Oct 8, 2026Contextual Correction of Parallel Draftsfor Speculative Decoding

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