From: Y <intruder_tkyf@yahoo.fr>
To: Bloat@lists.bufferbloat.net
Subject: Re: [Bloat] Tuning fq_codel: are there more best practices for slow connections? (<1mbit)
Date: Fri, 3 Nov 2017 01:58:29 +0900 [thread overview]
Message-ID: <e5d6e72b-1eac-6c77-ea85-ea4add606238@yahoo.fr> (raw)
In-Reply-To: <026B80D8-2452-4E9E-A85E-4FBD6BFB25A1@gmx.de>
Hi ,Moeller.
Fomula of target is 1643 bytes / 810kbps = 0.015846836.
It added ATM linklayer padding.
16ms plus 4ms as my sence :P
My connection is 12mbps/1mbps ADSL PPPoA line.
and I set 7Mbps/810kbps for bypass router buffer.
I changed Target 27ms Interval 540ms as you say( down delay plus upload
delay).
It works well , now .
Thank you.
Yutaka.
On 2017年11月02日 17:25, Sebastian Moeller wrote:
> Hi Y.
>
>
>> On Nov 2, 2017, at 07:42, Y <intruder_tkyf@yahoo.fr> wrote:
>>
>> 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.
> Under full saturation in theory you would expect the average latency to equal the sum of upstream target and downstream target (which in your case would be 20 + ???) in reality I often see something like 1.5 to 2 times the expected value (but I have never inquired any deeper, so that might be a measuring artifact)...
>
> Best Regards
>
>
>> 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?
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Bloat mailing list
>>>
>>> Bloat@lists.bufferbloat.net
>>> https://lists.bufferbloat.net/listinfo/bloat
>> _______________________________________________
>> Bloat mailing list
>> Bloat@lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/bloat
next prev parent reply other threads:[~2017-11-02 16:58 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-02 6:01 cloneman
2017-11-02 6:42 ` Y
2017-11-02 8:25 ` Sebastian Moeller
2017-11-02 16:33 ` Kathleen Nichols
2017-11-02 16:53 ` Y
2017-11-02 16:58 ` Y [this message]
2017-11-02 20:31 ` Sebastian Moeller
2017-11-03 0:31 ` Yutaka
2017-11-03 9:53 ` Sebastian Moeller
2017-11-03 10:10 ` Yutaka
2017-11-03 10:31 ` Sebastian Moeller
2017-11-03 10:51 ` Yutaka
2017-11-02 7:11 ` Jonathan Morton
2017-11-02 8:23 ` Sebastian Moeller
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