hesela.devFIOS
FIOS is a research operating-system I/O scheduler combining per-task time budgets, optional read preference, concurrent dispatch and anticipation for flash-storage fairness.
Unused timeslice survives task switches within an epoch. An exhausted task waits for renewal; fairness over that epoch is not a per-request latency guarantee. [1] [2]
Optional read preference can withhold writes while reads remain outstanding, but cannot preempt an already dispatched write. The authors allow disabling it when read/write interference is modest. [1]
Relations
- related
- I/O scheduler, Anticipatory scheduling, FlashFQ
Limitations
- The historical Linux prototype changed filesystem behavior and disabled journaling; it is not a contemporary NVMe performance ranking. [1]
Citations
- Park and Shen. FIOS: A Fair, Efficient Flash I/O Scheduler. FAST 2012, sections 4.1-4.4 and 5.
- Shen and Park. FlashFQ. USENIX ATC 2013, sections 3 and 6.
Further reading
Sources & caveats
- Primary-source synthesis; no scheduler implementation, hardware benchmark or performance replication was performed.