From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rob Gardner <rob.gardner@hp.com>
Subject: Re: CPU Utilization
Date: Mon, 12 Dec 2005 12:23:19 -0700
Message-ID: <439DCE27.3080807@hp.com>
References: <5440A5A36B8CED4B9F54524343CB6B68FD1300@xmb-rtp-215.amer.cisco.com>
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To: "Dave Thompson (davetho)" <davetho@cisco.com>
Cc: xen-devel@lists.xensource.com
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Dave Thompson (davetho) wrote:

>I have a question concerning the CPU utilization number provided by
>the 'xm top' command in xen 3.0.  I've noticed that if I run a TCP
>performance tool on domain 0 which simply receives and echos back
>a TCP stream, the output of 'xm top' during the test does not match
>up with the output of 'top' on domain 0 in terms of CPU utilization
>(nor with the CPU utilization computed by the test program).
>
>...
>
>Any idea why these displays disagree?
>  
>

Top shows cpu usage for user processes in dom0, while xm top shows cpu 
usage for the domain, which includes cpu time spent in the dom0 kernel. 
Perhaps the thing you're running incurs lots of kernel cpu time, but not 
user time?

Rob