Re: [Libvir] ANNOUNCE: Virt-top - a top-like utility for displaying virtualization stats
On Mon, Aug 06, 2007 at 10:15:48PM +0100, Richard W.M. Jones wrote:
There are a few data collection artifacts which need to be
investigated.
In particular, %CPU sometimes goes over 100%. Obviously accurate data
collection is an important goal for this tool.
AFAICT it is impossible to stop it going over 100% - we have same issue
in virt-manager when calculating CPU usage. To caculate the % usage you
are looking at the differential between CPU time from two calls to
virDomainGetInfo vs the time period between two gettimeofday() calls.
If the time delta between your gettimeofday() calls does not exactly
match the time delta between your virDomainGetInfo() calls, and the
domain you're measuring is very active then you can end up calcuating
100% occassionally. Not by much - typically < 1% over, but I
don't
really see any way around it.
Regards,
Dan.
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