{
  "title": "Full blocks and the same cache key are necessary for reuse",
  "caption": "Request B uses two cached full blocks with the same cache key again, then prefills its new tail. P=4 is an example. Prefill can include more work because of implementation details. Playback does not imply cache hits occur without cache-key checks. The author made this explanatory diagram.",
  "alt": "Prefix-cache flow: A prefills two full four-token blocks, and B uses the eight tokens again before it prefills its two-token tail.",
  "sources": [
    {
      "path": "content/blog/2026-06-11_life-of-a-request-vllm/post.md",
      "sha256": "158aa77041646bca8aba059344c4b6b0a6b451329b4a423e9c8027db8ba0304a",
      "description": "Current article explanation, equations, assumptions and retained citations."
    },
    {
      "path": "research/dynamic-mechanisms-2026-10-21/before/content/blog/2026-06-11_life-of-a-request-vllm/illustrations/04-prefix-cache-algorithm.svg",
      "sha256": "f9b43fc8d356556eb06a3e6840e17fd7fd0cad911debdb11a38c11e2cfa07355",
      "description": "Frozen prior illustration; exact pre-migration bytes retained."
    },
    {
      "path": "content/blog/2026-06-11_life-of-a-request-vllm/illustrations/source-notes.json",
      "description": "Existing article illustration provenance, retained unchanged."
    }
  ],
  "limitations": [
    "The execution is an example. Playback duration is not measured runtime."
  ]
}