A Solution to High Latencies Caused by I/O
summary
BFQ is an I/O scheduler implemented in the Linux kernel (in-tree since 4.12) that in tests on eMMC/SD cards and phones (HiKey and Pixel 2) cuts interactive latency dramatically: Facebook cold-start under a 15 MB/s background download goes from “hangs or times out” with legacy schedulers to about 6–10 s with BFQ (4 s overhead due to VM activity), desktop app startup replay tests on Debian 4.16-rc2 show idle ≈0.32 s vs non-BFQ tens of seconds while BFQ averages ~0.8–0.9 s, throughput cost small (occasional ~20% regressions); implements proportional sharing, latency-sensitive detection, and dispatch plugging.
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chapters (10)
- 0:00Introduction
- 0:18Agenda
- 1:40Schedulers
- 5:35Android
- 13:20Fast Network
- 18:50Linux
- 20:35Debian
- 24:10Analysis
- 27:40Results
- 29:45Questions
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