Re: [Bloat] Tuning fq_codel: are there more best practices for slow connections? (<1mbit)

[Y <intruder_tkyf@yahoo.fr>]

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hi.

My connection is 810kbps( <= 1Mbps).

This is my setting For Fq_codel,

quantum=300

target=20ms
interval=400ms

MTU=1478 (for PPPoA)

I cannot compare well. But A Latency is around 14ms-40ms.

Yutaka.


On 2017年11月02日 15:01, cloneman wrote:
> I'm trying to gather advice for people stuck on older connections. It 
> appears that having dedictated /micromanged tc classes greatly 
> outperforms the "no knobs" fq_codel approach for connections with  
> slow upload speed.
>
> When running a single file upload @350kbps , I've observed the 
> competing ICMP traffic quickly begin to drop (fq_codel) or be delayed 
> considerably ( under sfq). From reading the tuning best practices page 
> is not optimized for this scenario. (<2.5mbps)
> (https://www.bufferbloat.net/projects/codel/wiki/Best_practices_for_benchmarking_Codel_and_FQ_Codel/) fq_codel 
>
>
> Of particular concern is that a no-knobs SFQ works better for me than 
> an untuned codel ( more delay but much less loss for small flows). 
> People just flipping the fq_codel button on their router at these low 
> speeds could be doing themselves a disservice.
>
> I've toyed with increasing the target and this does solve the 
> excessive drops. I haven't played with limit and quantum all that much.
>
> My go-to solution for this would be different classes, 
> a.k.a.**traditional QoS. But ,  wouldn't it be possible to tune 
> fq_codel punish the large flows 'properly' for this very low bandwidth 
> scenario? Surely <1kb ICMP packets can squeeze through properly 
> without being dropped if there is 350kbps available, if the competing 
> flow is managed correctly.
>
> I could create a class filter by packet length, thereby moving 
> ICMP/VoIP to its own tc class, but  this goes against "no knobs" it 
> seems like I'm re-inventing the wheel of fair queuing - shouldn't the 
> smallest flows never be delayed/dropped automatically?
>
> Lowering Quantum below 1500 is confusing, serving a fractional packet 
> in a time interval?
>
> Is there real value in tuning fq_codel for these connections or should 
> people migrate to something else like nfq_codel?
>
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