Byte-Exact Certification of Multi-Stage Prefix Cache Resume

Establish byte-exact equivalence between multi-stage prefix-cache capture-and-resume and cold prefill of the same prompt across all stages of the distributed OpenVINO pipeline.

Background

The prefix-caching implementation serializes each stage’s opaque KV state and restores the states across the stage chain before prefilling only the uncached suffix. The single-stage warm path has been verified byte-identical to a cold full prefill.

The multi-stage protocol runs end-to-end on fleet hardware, but equivalent byte-exact certification has not been completed. This leaves unresolved whether distributed state capture, restoration, and suffix positioning preserve exact outputs in all stages.

References

We have verified the warm path byte-identical to a cold prefill of the full prompt on the single-stage configuration. The multi-stage protocol, in which each stage captures and restores only its own layers, runs end-to-end on fleet hardware but has not yet received the same byte-exact certification.

— Pre-Compiled Pipeline Shards for Distributed LLM Inference on Intel AI PC Fleets  (2608.19147 - Berenbaum et al., 19 Aug 2026) in Section 6.4, “Prefix Caching: KV Capture and Warm-Resume”