should we consider making CoDel the default to combat bufferbloat?

[John W. Linville]

On Thu, 2014-10-16 at 10:19 -0400, Josh Boyer wrote:
> On Wed, Oct 15, 2014 at 9:02 PM, Matthew Miller
> <mattdm at fedoraproject.org> wrote:
> > Reading https://lwn.net/Articles/616241/, getting myself in happily over my
> > level of actual knowledge about the state of things.
> >
> > From that article, it seems like it might be worth trying
> > net.core.default_qdisc = fq_codel by default. Just tossing this out there
> > for the consideration of someone who really knows what they're talking about
> > in this area.
> 
> I think the answer, as usual, is: "It depends."  It's not a silver
> bullet for all problems, but it would probably help in some cases.  I
> would actually think Server could use this more than Workstation, as
> the article points out that wireless networking has a number of other
> issues to consider.  I've added Neil on CC, who's probably much more
> equipped to weigh in on this than either of us.

I'll weigh-in here -- while fq_codel is not an ideal solution for
wireless (particularly .11n and .11ac) networks, IMHO it will be better
than the existing defaults for most users.  While there might be some
limited effects on throughput, the improvements in latency will be
generally worthwhile.  YMMV, of course.

> In any case, if this change is done it should be done in the
> initscripts package.  It's a runtime tunable and we don't need to be
> patching the kernel to change the default.

Agreed, of course.  The runtime tunability also provides an escape hatch
for anyone that is negatively impacted by this change of the default
qdisc.

I support the propose change to use the fq_codel default.

John
-- 
John W. Linville		Hope is a good breakfast, but it is a
linville at redhat.com			bad supper. -- Sir Francis Bacon