{
  "slug": "prefetch-trigger-distance",
  "term": "Prefetch trigger distance",
  "aliases": [],
  "definition": "Prefetch trigger distance specifies how far before the end of an already-prefetched sequence the next prefetch is initiated.",
  "note": "In AMP, g = 0 places the trigger on the last page; batch size p and trigger distance g are separate controls. [amp]\n\nThis policy variable is not a Linux readahead syscall argument or a nonblocking-I/O guarantee. [hesela-prefetch]",
  "related": [
    "prefetch-wastage",
    "readahead",
    "posix-fadv-willneed",
    "cache-pollution",
    "page-cache"
  ],
  "status": "research",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-18",
  "citations": [
    {
      "id": "amp",
      "label": "Gill and Bathen, FAST 2007",
      "title": "Binny S. Gill and Luis Angel D. Bathen. AMP: Adaptive Multi-stream Prefetching in a Shared Cache. FAST 2007, pp. 185-198; sections II-VI.",
      "url": "https://www.usenix.org/legacy/event/fast07/tech/full_papers/gill/gill.pdf",
      "accessed": "2026-10-18"
    },
    {
      "id": "hesela-prefetch",
      "title": "Hesela: fetch size, trigger timing and prefetch diagnostic evidence",
      "url": "https://hesela.com/analyses/o-direct-alignment-by-kernel/#shared-prefetch",
      "accessed": "2026-10-18"
    }
  ]
}