Bug #322

Testing BQL should happen in openwrt mainline

Added by Dave Täht on Dec 8, 2011. Updated on Apr 21, 2012.
Closed Urgent Dave Täht


BQL’s concept is simple and profound enough for others to test in mainline openwrt.

I need to stress that all BQL does at present is move the bufferbloat problem out of the
ethernet drivers and into the packet schedulers, where more packet bursts need to be shredded than
what the default pfifo_fast scheduler can do.

Also: BQL’s controller kind of bothers me, but applying hard limits to the amount of bytes in flight
worked well, in testing an earlier version.

Needed are:

  • ar71xx working on 3.1.5 - which will contain a fix to RED
  • BQL backport to 3.1.5 (I did v3, someone else is doing v4)
  • BQL driver support for selected devices (ag71xx) (done, untested)
  • Building openwrt with QFQ support in the scheduler (DRR is good too) (patches in cerowrt, currently)
  • update to iproute2 to at least the 3.0 level to get QFQ support (also patches in cerowrt, currently)
  • Scripts to engage TC and things like QFQ, SFQ, etc on top of line rate and HTB (deBloat.git)

All these patches are floating in loose formation. The ar71xx 3.1 backport arrived this morning…

Useful will be - closely tracking eric dumazet’s adaptive red work (which is now in net-next and can also be easily backported), as well as the related iproute2 changes -

most useful of all, for wireless, will be the upcoming ‘time in queue’ set of ideas, which affect the kernel and iproute as well.

That said, I think all the ideas are promising enough to actually do inside of openwrt, with the help of everyone expending enthusiasm on it all right now, and we will get better and more interesting results, faster.

Doing further work on these exciting bits merely inside of cerowrt would be self limiting.


Updated by Dave Täht on Apr 21, 2012.
Well, as 3.3 gets rolled out, it’s going to happen anyway. It would be good for the openwrt devs to be fully aware of interactions with TSO/GSO

This is a static export of the original bufferbloat.net issue database. As such, no further commenting is possible; the information is solely here for archival purposes.
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


Comcast Research Innovation Fund
Nlnet Foundation
Shuttleworth Foundation

Bufferbloat Related Projects

OpenWrt Project
Congestion Control Blog
Flent Network Test Suite
The Cake shaper
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".