netdev - Re: TCP connection stalls under 2.6.24.7

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Message-Id: <200807251734.27743.thomas.jarosch@intra2net.com>
Date:	Fri, 25 Jul 2008 17:34:26 +0200
From:	Thomas Jarosch <thomas.jarosch@...ra2net.com>
To:	"Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi>
Cc:	Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>,
	Netdev <netdev@...r.kernel.org>,
	Patrick McHardy <kaber@...sh.net>,
	Sven Riedel <sr@...urenet.de>,
	Netfilter Developer Mailing List 
	<netfilter-devel@...r.kernel.org>,
	"Dâniel Fraga" <fragabr@...il.com>,
	David Miller <davem@...emloft.net>
Subject: Re: TCP connection stalls under 2.6.24.7

Ilpo,

On Friday, 25. July 2008 16:06:04 Ilpo Järvinen wrote:
> I guess the patch below would be enough in itself to create the desired
> effect (though "desired" is hardly a negative enough word to describe a
> workaround of this kind). 

Yeah, the result feels good enough for me. Here's the latest tcpdump
before I run out of good filenames for the dumps:
http://www.intra2net.com/de/download/tcpdump/tcp_frto_combined_patch.tar.bz2

> Ie., in the worst case 6.8% of your link's capacity was wasted during the
> transfer due to inefficiency cause by that middlebox, not counting the
> under-utilization that occurs both because of a small window or a wait for
> RTOs, not bad result at all... :-D

IIRC our outbound box does traffic shaping, so some percents are to be 
accounted to packets being dropped to slow down the connection a bit 
if they come (in) too fast.

Anyway, we now just have to flip a coin if this gets into the kernel
or not :-) I really hope this could save someone from doing
the same debug session all over again...

Thanks for the hard work you put into debugging this.

Thomas
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