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Date: Wed, 4 Jul 2012 17:48:56 +0200
From: Luigi Rizzo <rizzo@iet.unipi.it>
To: "Alexander V. Chernikov" <melifaro@FreeBSD.org>
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Cc: Doug Barton <dougb@freebsd.org>, net@freebsd.org
Subject: Re: FreeBSD 10G forwarding performance @Intel
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On Wed, Jul 04, 2012 at 01:54:01PM +0400, Alexander V. Chernikov wrote:
> On 04.07.2012 13:12, Luigi Rizzo wrote:
> >Alex,
> >i am sure you are aware that in FreeBSD we have netmap too
> Yes, I'm aware of that :)
> 
> >which is probably a lot more usable than packetshader
> >(hw independent, included in the OS, also works on linux...)
> I'm actually not talking about usability and comparison here :). Thay 
> have nice idea and nice performance graphs. And packetshader is actually 
> _platform_ with fast packet delivery being one (and the only open) part 
> of platform.

i am not sure if i should read the above as a feature or a limitation :)

> 
> Their graphs shows 40MPPS (27G/64byte) CPU-only IPv4 packet forwarding 
> on "two four-core Intel Nehalem CPUs (2.66GHz)" which illustrates 
> software routing possibilities quite clearly.

i suggest to be cautious about graphs in papers (including mine) and
rely on numbers you can reproduce yourself.
As your nice experiments showed (i especially liked when you moved
from one /24 to four /28 routes), at these speeds a factor
of 2 or more in throughput can easily arise from tiny changes
in configurations, bus, memory and CPU speeds, and so on.

cheers
luigi