From: Carsten Wolff <carsten@wolffcarsten.de>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Esztermann, Ansgar" <Ansgar.Esztermann@mpi-bpc.mpg.de>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: TCP fast retransmit
Date: Tue, 13 Dec 2011 15:59:17 +0100 [thread overview]
Message-ID: <201112131559.17969.carsten@wolffcarsten.de> (raw)
In-Reply-To: <1323786660.2744.1.camel@edumazet-laptop>
On Tuesday 13 December 2011, you wrote:
> Le mardi 13 décembre 2011 à 15:05 +0100, Esztermann, Ansgar a écrit :
> > On Dec 9, 2011, at 17:31 , Eric Dumazet wrote:
> > >>> It seems you have a lot of packet reorders.
> > >>>
> > >>> Are you using multipath or some channel bonding ?
> > >>
> > >> Not that I am aware of (i.e. not on our end). However, the connection
> > >> will probably routed through a firewall. I will have to check if it is
> > >> configured to avoid reordering.
> > >
> > > Is it a linux based firewall ?
> >
> > No, it's Cisco.
>
> OK
>
> You could increase /proc/sys/net/ipv4/tcp_reordering from 3 to 16
>
> (Not sure it will change anything, since its kinda dynamic for a tcp
> session)
It's dynamic, but the sysctl changes the dynamic a lot, because its the
minimum value of the dupack threshold. Be sure not to set this too high, or
you will risk a lot of RTOs, which should kill performance even more
thoroughly.
Carsten
next prev parent reply other threads:[~2011-12-13 14:59 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-25 13:33 TCP fast retransmit Esztermann, Ansgar
2011-11-25 16:36 ` Eric Dumazet
2011-11-25 16:39 ` Eric Dumazet
2011-11-29 9:00 ` Esztermann, Ansgar
2011-12-09 13:34 ` Esztermann, Ansgar
2011-12-09 14:43 ` Eric Dumazet
2011-12-09 16:17 ` Esztermann, Ansgar
2011-12-09 16:31 ` Eric Dumazet
2011-12-13 14:05 ` Esztermann, Ansgar
2011-12-13 14:31 ` Eric Dumazet
2011-12-13 14:59 ` Carsten Wolff [this message]
2011-12-14 19:00 ` Yuchung Cheng
2011-12-14 22:31 ` Eric Dumazet
2011-12-15 7:41 ` Carsten Wolff
2011-12-15 8:24 ` Eric Dumazet
2011-12-16 15:53 ` Esztermann, Ansgar
2011-11-25 16:57 ` Ilpo Järvinen
2011-11-28 21:17 ` Yuchung Cheng
2011-11-29 9:00 ` Esztermann, Ansgar
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