[et-mgmt-tools] About CPU Usage of virt-manager

[Daniel P. Berrange]

On Thu, Feb 22, 2007 at 03:44:12PM +0900, Masayuki Sunou wrote:
> Hi,
> 
> I have a question about CPU Usage of virt-manager.
> 
> Virt-manager calculates CPU Usage based on physical CPU.
> Because of that, when the host has many CPU, guest's CPU Usage is difficult 
> to know. (SMP etc.)
> 
> example:
>   When the host has 32 CPU, and guest's CPU Usage is 100%, virt-manager
>   displays CPU Usage as 3%.
>   --> 100%/32CPU=3%
> 
> Therefore, I think that virt-manager should calculate CPU Usage based on
> virtual CPU.(like "xentop")
>
> Because "Xentop" calculates CPU Usage based on virtual CPU, I think that
> virt-manager should also calculate CPU Usage based on virtual CPU. 

The reason for calculating usage based on physical CPU is to illustrate
what % of the  host machine's resources are being used by a particular
machine. eg it makes is very easy to see that 'Guest X' is taking up 50%
of the host's compute cycles. Simiarly memory is calculated against
physical RAM. While calculating CPU usage based on virtual CPUs would 
make it easier to see how much of its own allocation a guest is using, it
would be harder to visualize overall host utilization. 

Perhaps we need to support both..

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  -=|