[Bloat] Fwd: [Bug 1436945] Re: devel: consider fq_codel as the default qdisc for networking

Mario Hock mario.hock at kit.edu
Tue Jun 5 03:44:25 EDT 2018


Am 05.06.2018 um 01:00 schrieb David Lang:
> 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.

Just to make sure that I got your answer correctly. The benefit for 
endsystems comes from the "fq" (flow queuing) part, not from the "codel" 
part of fq_codel?

Mario Hock



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