From mboxrd@z Thu Jan  1 00:00:00 1970
From: Riccardo Veraldi <Riccardo.Veraldi@cnaf.infn.it>
Subject: kvm network performance
Date: Tue, 10 Feb 2009 17:11:29 +0100
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Hello,
I am using kvm83 on Centos 5.2
I did some iperf test on my kvm guest and I got the following results 
over a 1GB connection:

~650Mbit/s inbound
~250Mbit/s outbound

that is  performance appears to be asymmetric.

Is this normal ?

The inbound data flow is quite impressive as performance but the 
outbound is poorer.
How come this happens ?

I di dtest on the bare machine ad it is around 800Mbit/s inbound and 
outbound.

any hints ?

thank you

Rick