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From: Patrick McManus <mcmanus@ducksong.com>
To: "Brandeburg, Jesse" <jesse.brandeburg@intel.com>
Cc: netdev@vger.kernel.org
Subject: RE: 2.6.27 problem with shaping using netem/ifb (regression?) [TSO]
Date: Wed, 01 Oct 2008 21:55:42 -0400	[thread overview]
Message-ID: <1222912542.6395.30.camel@tng> (raw)
In-Reply-To: <36D9DB17C6DE9E40B059440DB8D95F52064FB007@orsmsx418.amr.corp.intel.com>

On Wed, 2008-10-01 at 18:42 -0700, Brandeburg, Jesse wrote:
> > Any thoughts on where to look? I hope attaching the script is helpful
> -
> > it is pretty self evident when running it if things are working ok.
> > This
> > is all on amd64 if that is relevant.
> 
> Have you tried disabling TSO and/or GSO on the loopback device?

for some reason with loopback that didn't come to mind. It's a good
suggestion, and indeed is the crux of the problem. Thanks!

Disabling TSO (ethtool -K lo tso off) fixes the problem. GSO has no
impact.

probly not relevant, but worth noting - the scripts also set the MTU of
lo to 1500 down from the default 16436



  reply	other threads:[~2008-10-02  1:55 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-01 23:04 2.6.27 problem with shaping using netem/ifb (regression?) Patrick McManus
2008-10-02  1:42 ` Brandeburg, Jesse
2008-10-02  1:55   ` Patrick McManus [this message]
2008-10-02 15:49     ` 2.6.27 problem with shaping using netem/ifb (regression?) [TSO] Patrick McManus

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