General list for discussing Bufferbloat
 help / color / mirror / Atom feed
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


  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: https://lists.bufferbloat.net/postorius/lists/bloat.lists.bufferbloat.net/

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=e5d6e72b-1eac-6c77-ea85-ea4add606238@yahoo.fr \
    --to=intruder_tkyf@yahoo.fr \
    --cc=Bloat@lists.bufferbloat.net \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox