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From: Jonathan Morton <chromatix99@gmail.com>
To: Juliusz Chroboczek <jch@irif.fr>
Cc: Dave Taht <dave.taht@gmail.com>,
	Make-Wifi-fast <make-wifi-fast@lists.bufferbloat.net>,
	babel-users@lists.alioth.debian.org
Subject: Re: [Make-wifi-fast] [Babel-users] reducing delays in wifi mcast queues
Date: Wed, 19 Sep 2018 03:07:08 +0300	[thread overview]
Message-ID: <B8287435-A6CC-47E0-93C1-B40479D07B42@gmail.com> (raw)
In-Reply-To: <8736u6cpyu.wl-jch@irif.fr>

> On 19 Sep, 2018, at 3:04 am, Juliusz Chroboczek <jch@irif.fr> wrote:
> 
>> Recently I tried to deploy a few babel 1.8.2 nodes with the latest
>> openwrt, which I had to back out rapidly because I was dropping so many
>> babel packets under contention.
> 
> That's interesting.  Could I please see a log?
> 
>> A patch to universally enable babel ecn in net.c "solves" this problem,
> 
> Interesting.  AFAIK, ECN is only considered by AQM queues, so this implies
> there's a queue in the way that's dropping Babel packets.  Perhaps this
> queue could be convinced to treat Babel packets specially without having
> to hack around it using ECN?  Or perhaps, if we know which queue that is,
> we could modify Babel's packet scheduling to be more AQM friendly?

I assume it's the make-wifi-fast logic, which has fq_codel baked into the Linux wifi stack.  That would react to congestion and ECN as described.

 - Jonathan Morton


  reply	other threads:[~2018-09-19  0:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-19  4:15 [Make-wifi-fast] " Dave Taht
2018-09-18 23:19 ` [Make-wifi-fast] [Babel-users] " Juliusz Chroboczek
2018-09-18 23:31   ` Dave Taht
2018-09-19  0:04     ` Juliusz Chroboczek
2018-09-19  0:07       ` Jonathan Morton [this message]
2018-09-19  0:32       ` Dave Taht
2018-09-19  0:43         ` Juliusz Chroboczek
2018-09-19  0:53           ` Dave Taht
2018-09-19  6:05           ` Jonathan Morton

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