From: Pete Heist <peteheist@gmail.com>
To: Jonathan Morton <chromatix99@gmail.com>
Cc: Cake List <cake@lists.bufferbloat.net>
Subject: Re: [Cake] lan keyword affects host fairness
Date: Thu, 23 Nov 2017 11:25:32 +0100 [thread overview]
Message-ID: <52C2B216-220C-4C17-882C-9994867E86BB@gmail.com> (raw)
In-Reply-To: <CAJq5cE08yhPxOJwCBbHFQiQ1Hp4_Zff2f7Oia+a5S=tdNZBJNg@mail.gmail.com>
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> On Nov 23, 2017, at 10:44 AM, Jonathan Morton <chromatix99@gmail.com> wrote:
> This is most likely an interaction of the AQM with Linux' scheduling latency.
>
> At the 'lan' setting, the time comstants are similar in magnitude to the delays induced by Linux itself, so congestion might be signalled prematurely. The flows will then become sparse and total throughput reduced, leaving little or no back-pressure for the fairness logic to work against.
>
> For this reason, you might have better luck with the next higher RTT setting.
>
Thanks…and using ‘metro’ (rtt 10ms) does improve things (two more tests at the end):
https://docs.google.com/spreadsheets/d/1SMXWw2fLfmBRU622urfdvA_Ujsuf_KQ4P3uyOH1skOM/edit#gid=2072687073
In both cases, soft rate limiting to 950mbit when using lower RTTs works better than relying on bql for the back-pressure (if I’m saying that right).
So it just might be a thing (for the man page?) to avoid confusion. Or a warning emitted in some cases? Maybe there are other opinions on that...
Pete
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next prev parent reply other threads:[~2017-11-23 10:25 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-23 9:21 Pete Heist
2017-11-23 9:44 ` Jonathan Morton
2017-11-23 10:25 ` Pete Heist [this message]
2017-11-23 17:03 ` Dave Taht
2017-11-24 11:21 ` Toke Høiland-Jørgensen
2017-11-24 12:06 ` Sebastian Moeller
2017-11-24 13:15 ` Marcelo Ricardo Leitner
2017-11-24 13:49 ` Pete Heist
2017-11-24 19:41 ` Pete Heist
2017-11-24 19:48 ` Jonathan Morton
2017-11-24 20:24 ` Pete Heist
[not found] ` <CAJq5cE2eX4AJCPaBL-FW7Oj_afthXKnZn1RHQPH1VBCJfCyXDg@mail.gmail.com>
2017-11-24 20:32 ` Jonathan Morton
2017-11-25 7:18 ` Pete Heist
2017-11-24 20:03 ` Dave Taht
2017-11-24 20:40 ` Dave Taht
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