Higher than expected CPU use for idle VMs

t0ddjames

New Member
Jul 17, 2016
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0
1
I tried searching but did not find any answers that relate to my specific problem.

I have Proxmox VE 4.2 installed with two Ubuntu 16.04 Server VMs. One acts as a router for my home network, and the other has a Java web app that runs some third-party software.

CPU usage from within both VMs appears to be close to or exactly 0%. However, Proxmox shows the router VM hovering at ~1% CPU usage consistently, and the Java web app VM at ~6%.

Indeed, I can confirm via the top command on the Proxmox host that two kvm processes are consuming ~6% CPU and ~3% CPU.

I'm wondering what the difference in usage is? Why is so much CPU being consumed on the host when it seems the VMs are essentially idle?

I'm sure there are some details I have not included that will be helpful in figuring this out, I just don't know what they are. So feel free to ask me to post any other necessary configuration details.
 
I'm wondering what the difference in usage is? Why is so much CPU being consumed on the host when it seems the VMs are essentially idle?

This can be driver emulation overhead, or simply some kernel activities inside the VM (which is not correctly accounted from inside the VMs)
 

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