{
  "slug": "fastmap",
  "term": "FastMap",
  "aliases": [],
  "definition": "FastMap is a research redesign of Linux's memory-mapped I/O path that targets synchronization bottlenecks in multicore storage workloads.",
  "note": "Design: per-core structures and separate clean/dirty tracking reduce shared contention. [fastmap-paper]\n\nScope: prototype evaluation, not a stock Linux feature or a transaction guarantee. See the companion source review for benchmark-label limitations. [hesela-fastmap]",
  "status": "research",
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-18",
  "advantages": [
    "Reduces contention in the evaluated mapping path."
  ],
  "limitations": [
    "Performance depends on implementation, workload and device."
  ],
  "related": [
    "memory-mapped-file",
    "page-cache",
    "msync",
    "direct-io"
  ],
  "citations": [
    {
      "id": "fastmap-paper",
      "title": "Papagiannis et al., Optimizing Memory-mapped I/O for Fast Storage Devices, USENIX ATC 2020, sections 3-5",
      "url": "https://www.usenix.org/system/files/atc20-papagiannis.pdf",
      "accessed": "2026-10-18"
    },
    {
      "id": "hesela-fastmap",
      "title": "Hesela: mmap literature and FastMap benchmark scope",
      "url": "https://hesela.com/analyses/mmap-visibility-size-durability/#fastmap-scope",
      "accessed": "2026-10-18"
    }
  ]
}