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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Juliusz Chroboczek <jch@pps.univ-paris-diderot.fr>
Cc: bloat <bloat@lists.bufferbloat.net>
Subject: Re: [Bloat] AQM and PPP on Linux
Date: Tue, 28 Jul 2015 16:18:42 +0200	[thread overview]
Message-ID: <1438093122.20182.46.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <876154qtkt.wl-jch@pps.univ-paris-diderot.fr>

On Tue, 2015-07-28 at 15:50 +0200, Juliusz Chroboczek wrote:
> > What distro are you on?
> 
> Debian.  (One machine stable, one testing.)
> 
> > There's a sysctl to set the default qdisc: net.core.default_qdisc.
> 
>     $ sysctl -a | grep default_qdisc
>     net.core.default_qdisc = pfifo_fast
> 
> > Set this to fq_codel and you should be good to go.
> 
> Is that safe?  I'm thinking lo and virtual interfaces.

Unless some user space script change it, virtual interfaces have
txqueuelen = 0, so no qdisc is set up on them

$ ifconfig lo | grep txqueuelen
          collisions:0 txqueuelen:0

$ tc -s -d qdisc sh dev lo
<empty>

So yes, this is reasonably safe to change net.core.default_qdisc



  parent reply	other threads:[~2015-07-28 14:18 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-28 13:09 Juliusz Chroboczek
2015-07-28 13:33 ` Toke Høiland-Jørgensen
2015-07-28 13:50   ` Juliusz Chroboczek
2015-07-28 14:05     ` Toke Høiland-Jørgensen
2015-07-28 14:11       ` Simon Barber
2015-07-28 14:21         ` Eric Dumazet
2015-07-28 14:31           ` Simon Barber
2015-07-28 14:43             ` Jonathan Morton
2015-07-28 14:49             ` Eric Dumazet
2015-07-28 14:55               ` Eric Dumazet
2015-07-28 16:02               ` Alan Jenkins
2015-07-28 16:22             ` Sebastian Moeller
2015-07-28 17:11               ` Michael Welzl
2015-07-29  7:19         ` David Lang
2015-07-28 19:20       ` Juliusz Chroboczek
2015-07-28 19:29         ` Alan Jenkins
2015-07-28 14:18     ` Eric Dumazet [this message]
2015-07-28 14:44 ` Dave Taht
2015-07-28 14:52   ` Eric Dumazet
2015-07-28 19:24   ` Juliusz Chroboczek
2015-07-28 19:31     ` Bill Ver Steeg (versteb)
2015-07-28 20:10     ` Alan Jenkins
2015-07-28 20:45       ` Alan Jenkins
2015-07-29 13:15   ` Stefan Alfredsson
2015-07-29 13:41     ` Dave Taht

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