[libvirt-users] Source code of virt-manager

[Michal Privoznik]

On 05.07.2014 19:44, Restituto Marcus Arevalo wrote:
> Hi,
>
>      Does anyone know where I could view the source code of
> virt-manager? Because I'm trying to learn how the virt-manager gets the
> CPU usage of a VM(the graph it displays). I'm trying to make a program
> using java that gets the CPU usage of a VM in KVM. Anybody have
> suggestions on where I could start? Thanks

The virt-manager source code can be found here:

https://git.fedorahosted.org/git/virt-manager.git

To check it out use:

git clone git://git.fedorahosted.org/git/virt-manager.git virt-manager.git


The CPU usage of a domain is queried using virDomainGetInfo. The CPU 
usage is then calculated as (in a crippled C):

while (1) {
   time1 = now();
   virDomainGetInfo(dom, &info);
   cpu1 = info.cpuTime;
   sleep(500);  // sleep some time
   time2 = now();
   virDomainGetInfo(dom, &info);
   cpu2 = info.cpuTime;

   cpuUsagePercent = (cpu2 - cpu1) / (time2 - time1) * 100;
}

Michal