BQL enabled drivers

Queue Disciplines such as fq_codel and fq need the underlying buffering of the device and device driver well controlled. Under Linux, the mechanism to do so is called Byte Queue Limits (BQL), which needs a small amount of driver support to enable.

This is a partial list of the known BQL-enabled device drivers for Linux as of version 3.14. Also see the list at Best practices for benchmarking Codel and FQ Codel

  • Intel e1000e, e1000, ixgbe, ivb40evf,i40e
  • Atheros ar71xx, alx
  • Nvidia forcedeath
  • Marvell sky2, skge
  • Broadcom bnx2, tg3, b44
  • Mellanox mlx4
  • Freescale gianfar
  • Realtek 8139
  • Isilicon hix5hd2

Highly desirable to BQL enable

  • Cisco, AMD, Xilinx and other manufacturers
  • Kirkwood (dreamplug, guruplug etc)
  • net-usb (patch discussed on cerowrt-devel) (raspery pi uses usb to network)
  • r8169 (buggy in 3.6 and earlier, currently reverted)
  • niu (same problem basically as r8169, also currently reverted)

There are 7 out of tree BQL drivers here that could use testing and integration: http://www.mcmilk.de/projects/linux-bql/

Other subsystems

BQL is desirable for devices running at line rate. It is not required for soft rate shapers such as hfsc and htb, which are independent of the underlying wire rate.

Similar techniques to BQL could be used at other layers in the stack, such as various forms of wireless, usb network devices, and adsl. But adding this technique is going to be really hard for wireless .

To edit this page, submit a pull request to the Github repository.
RSS feed

Recent Updates

Oct 20, 2023 Wiki page
What Can I Do About Bufferbloat?
Dec 3, 2022 Wiki page
Codel Wiki
Jun 11, 2022 Wiki page
More about Bufferbloat
Jun 11, 2022 Wiki page
Tests for Bufferbloat
Dec 7, 2021 Wiki page
Getting SQM Running Right

Find us elsewhere

Bufferbloat Mailing Lists
#bufferbloat on Twitter
Google+ group
Archived Bufferbloat pages from the Wayback Machine

Sponsors

Comcast Research Innovation Fund
Nlnet Foundation
Shuttleworth Foundation
GoFundMe

Bufferbloat Related Projects

OpenWrt Project
Congestion Control Blog
Flent Network Test Suite
Sqm-Scripts
The Cake shaper
AQMs in BSD
IETF AQM WG
CeroWrt (where it all started)

Network Performance Related Resources


Jim Gettys' Blog - The chairman of the Fjord
Toke's Blog - Karlstad University's work on bloat
Voip Users Conference - Weekly Videoconference mostly about voip
Candelatech - A wifi testing company that "gets it".