should we consider making CoDel the default to combat bufferbloat?

[Josh Boyer]

On Fri, Oct 17, 2014 at 11:01 AM, Michal Schmidt <mschmidt at redhat.com> wrote:
> Dne 16.10.2014 v 16:19 Josh Boyer napsal(a):
>
>> 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.
>>
>> 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.
>
>
> Josh,
> we're considering adding "net.core.default_qdisc = fq_codel" to
> the default sysctl config shipped with systemd.
>
> Assuming we do that, would you change CONFIG_NET_SCH_FQ_CODEL
> in the Fedora config to make it built-in rather than a module?

I've made this change in 3.17.1-301.fc21.  It doesn't change the
default by itself so it seemed safe to do either way and avoids the
SELinux issue.

josh