Strange display of CPU usage

[Marcus Mülbüsch, AS-Infodienste GmbH (Systemadministration)]

   I have it seen sometimes, shortly after I start monit and issue a 
'monit summary' that the CPU usage lists negative values:


> System 'name.tld'
>   status                            running
>   monitoring status                 monitored
>   load average                      [0.00] [0.11] [0.15]
>   cpu                               -1.0%us -1.0%sy -1.0%wa
>   memory usage                      603584 kB [15.2%]
>   data collected                    Tue Sep 14 14:00:41 2010

   This is not exactly serious, as it disappears after the first 
minute; but can it be true? Do I miss something of how CPU resources are 
really measured?

   Using "This is monit version 5.1.1" on "2.6.22-vs2.2.0.7-gentoo" 
inside a VServer guests (but it happens on the VServer host, too.)

Marcus