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Date: Fri, 30 Jul 2010 11:26:31 -0600
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Subject: Asymtopic Behavior in IP Hashing Performance All Kernels 2.6.28.10 
	and above
From: Jeffrey Merkey <jeffmerkey@gmail.com>
To: linux-kernel@vger.kernel.org
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With the cwgen.ko packet generator set to the following range of
settings on a Compaw Presario 2200 laptop, I see the following
performance behavior on system throughput:

CURRENT
http://open-cworthy-linux-packet-generator.googlecode.com/files/cwgen-07-29-2010.tar.gz

REPOSITORIES
http://code.google.com/p/open-cworthy-linux-packet-generator/
http://sourceforge.net/projects/cworthypktgen/

Interface: lo
Mode: continuous
IP Mode: Random Source/IP/Ports
pktsize: 1500
Interpacket Gap Time:  0 ns

runs at 89 megabytes per second throughput

Interface: lo
Mode: Continuous
IP Mode: Static IP/Static Ports
Source: 127.0.0.1
Dest 127.0.0.2
Range: 16 addresses
pktsize: 1500
Interpacket Gap Time:  0 ns

runs at 217 megabytes per second throughput

There is a significant performance drop (to roughly 1/3) when large
numbers of random IP addresses are routed through the IP stack.
Utilization does not seem to vary much, but the routing throughput
drops drastically.

Jeff Merkey
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