From: Jesper Dangaard Brouer <jbrouer@redhat.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Jesper Dangaard Brouer" <brouer@redhat.com>,
"Stephen Hemminger" <stephen@networkplumber.org>,
"David Miller" <davem@redhat.com>,
j.vimal@gmail.com, "Michal Soltys" <soltys@ziu.info>,
"Mike Frysinger" <vapier@gentoo.org>,
"Jussi Kivilinna" <jussi.kivilinna@mbnet.fi>,
"Patrick McHardy" <kaber@trash.net>,
"Jiri Pirko" <jpirko@redhat.com>,
"Toke Høiland-Jørgensen" <toke@toke.dk>,
"Dave Taht" <dave.taht@gmail.com>,
netdev@vger.kernel.org, bloat@lists.bufferbloat.net,
"Dan Siemon" <dan@coverfire.com>,
"Jim Gettys" <jg@freedesktop.org>,
"Steven Barth" <cyrus@openwrt.org>,
"Felix Fietkau" <nbd@nbd.name>, "Jiri Benc" <jbenc@redhat.com>
Subject: Re: tc linklayer ADSL calc broken after commit 56b765b79 (htb: improved accuracy at high rates)
Date: Thu, 30 May 2013 09:51:17 +0200 [thread overview]
Message-ID: <20130530095117.503eeee7@redhat.com> (raw)
In-Reply-To: <1369842724.5109.44.camel@edumazet-glaptop>
On Wed, 29 May 2013 08:52:04 -0700
Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Wed, 2013-05-29 at 15:13 +0200, Jesper Dangaard Brouer wrote:
> > I recently discovered that the (traffic control) tc linklayer
> > calculations for ATM/ADSL have been broken by:
> > commit 56b765b79 (htb: improved accuracy at high rates).
> >
> > Thus, people shaping on ADSL links, using e.g.:
> > tc class add ... htb rate X ceil Y linklayer atm overhead 10
> >
> > Will no-longer get ATM cell tax/overhead adjusted.
> >
> > How can we solve/fix this?
> > Perhaps we can change to use the "stab" system instead (as it does
> > not seem to be broken by the commit).
> >
[...]
>
> stab suffers from the same problem : its table driven, so works only
> for packet smaller than a given size.
You are referring to GSO/GRO packets. Yes, one must disable GSO for
this to work. Regardless ATM/ADSL, you should disable GSO when shaping
at low speeds. Sending 64000 byte on a 512Kbit/s takes approx 1 sec.
http://netoptimizer.blogspot.dk/2010/12/buffer-bloat-calculations.html
> I am not sure it will solve the ATM logic (with the 5 bytes overhead
> per 48 bytes cell)
Are you talking about, that for GSO frames we are not adding a encap
overhead to each "sub" skb.
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Sr. Network Kernel Developer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2013-05-30 7:51 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-29 13:13 tc linklayer ADSL calc broken after commit 56b765b79 (htb: improved accuracy at high rates) Jesper Dangaard Brouer
2013-05-29 15:52 ` Eric Dumazet
2013-05-29 22:50 ` Stephen Hemminger
2013-05-29 23:18 ` Eric Dumazet
2013-05-30 9:15 ` Jesper Dangaard Brouer
2013-05-30 9:52 ` [Bloat] " Steinar H. Gunderson
[not found] ` <20130529155034.334092c5-We1ePj4FEcvRI77zikRAJc56i+j3xesD0e7PPNI6Mm0@public.gmane.org>
2013-05-30 0:34 ` Dave Taht
2013-05-30 8:09 ` Jesper Dangaard Brouer
2013-05-30 7:51 ` Jesper Dangaard Brouer [this message]
2013-05-30 14:39 ` Eric Dumazet
2013-05-30 15:55 ` Jesper Dangaard Brouer
2013-05-30 16:29 ` Jussi Kivilinna
2013-06-02 21:15 ` Eric Dumazet
2013-06-02 21:33 ` [PATCH iproute2] htb: report overhead attribute Eric Dumazet
2013-06-03 15:45 ` Rick Jones
2013-06-03 15:56 ` Eric Dumazet
2013-06-04 11:11 ` Jesper Dangaard Brouer
2013-06-04 13:58 ` Eric Dumazet
2013-06-04 15:08 ` Jesper Dangaard Brouer
2013-06-03 19:50 ` Jussi Kivilinna
2013-06-07 15:56 ` Stephen Hemminger
2013-06-07 16:00 ` Eric Dumazet
2013-06-04 12:13 ` Bad shaping at low rates, after commit 56b765b79 (htb: improved accuracy at high rates) Jesper Dangaard Brouer
2013-06-04 15:18 ` Eric Dumazet
2013-06-04 15:55 ` Eric Dumazet
2013-06-04 16:02 ` Eric Dumazet
2013-06-04 17:11 ` [PATCH] net_sched: htb: do not mix 1ns and 64ns time units Eric Dumazet
2013-06-04 20:21 ` Jesper Dangaard Brouer
[not found] ` <20130604222135.67eedab8-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2013-06-04 20:26 ` Dave Taht
2013-06-04 21:02 ` Eric Dumazet
2013-06-04 20:50 ` Eric Dumazet
2013-06-05 0:44 ` David Miller
2013-06-06 13:55 ` RFC: Proposed fix for tc linklayer calc broken after commit 56b765b79 (htb: improved accuracy at high rates) Jesper Dangaard Brouer
2013-06-06 14:28 ` Eric Dumazet
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