[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

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.
-- 
|=- Red Hat, Engineering, Emerging Technologies, Boston.  +1 978 392 2496 -=|
|=-           Perl modules: http://search.cpan.org/~danberr/              -=|
|=-               Projects: http://freshmeat.net/~danielpb/               -=|
|=-  GnuPG: 7D3B9505   F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505  -=| 


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]