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From: David Lang <david@lang.hm>
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To: "Bless, Roland (TM)" <roland.bless@kit.edu>
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Subject: Re: [Bloat] Fwd: [Bug 1436945] Re: devel: consider fq_codel as the
 default qdisc for networking
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On Mon, 4 Jun 2018, Bless, Roland (TM) wrote:

> Hi,
>
> Am 24.05.2018 um 17:38 schrieb Jan Ceuleers:
>> Took 3 years after Dave approached them, but Ubuntu is finally adopting
>> fq_codel as the default qdisc.
>
> Yes, if the Linux kernel is forwarding packets it makes a lot of sense,
> but I don't understand why it make sense for ordinary end-systems.
> Didn't Byte Queue Limits (BQL) suffice? Just curious...

no, BQL makes things much better (and make it possible for more advanced quueing 
to take place), but you can still run into problems where a bulk stream can 
flood the output queue so that other traffic suffers badly.

with fq_codel, the available bandwidth is distributed in a way that ends up 
being much more functional.

It turns out that the behavior to prioritize new and sparse connections 
significantly improves perceived performance (no more long delays in DNS lookups 
before you start doing any real work for example)

without BQL, you can't even see the rest of the problems, but BQL doesn't solve 
everything.

David Lang