Why does Virtual Machine Manager not report CPU usage any more?

A few fedora releases ago, Virtual Machine Manager (VMM) stopped reporting CPU usage and Host CPU usage level. These were the two default graphs shown in VMM. I’m not sure quite how to troubleshoot this problem. The memory useage and Disk I/O graphs are working, but not the CPU graphs.

Any ideas?

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Hello @pdestefa
Could you share a screenshot?

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Sure. Here is a screen shot of the performance “tab” of one of my VMs. The period shown includes boot time, login, and running sysbench CPU test for 10 seconds. The VMM overview of all the VMs also shows an empty graph for CPU and Host CPU for this period. But you can see that Disk and Memory is being reported.

Mmm. Strange.
It works here.

Does this happen with any VM? Also with a brand new one?

Make sure you have enabled:
Virtual Machine Manager > View > Graph > Guest/Host CPU Usage

I haven’t created a new VM in a while, but this happens for three of my VMs. I’ll check some other VMs that I haven’t used in a long time, too, and get back to you. I’ll try a new VM too, but what if that works? Think that will tell me how to fix existing VMs?

I cloned a VM a few months ago, is that the same as building a new VM?

Regarding the View menu, both are checked. I “see” the graphs for CPU and Host CPU in the VMM window for all VMs, but they just show no data all the time, like they are off even when they are on.

Do you think this could have to do with the CPU Configuration? Of the two VMs that don’t report CPU stats that I have tested recently, one is Hypervisor Default, and I’m not sure what that means, and the other is “Copy host CPU configuration”. I’ll try some of these ideas you have given me tomorrow.

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Actually, I confirm the issue for Fedora 31 and KVM/QEMU guests.
Guest OS and CPU configuration seem to be irrelevant.
I tested only qemu:///session, not qemu:///system.

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Good catch @vgaetera
I can instead confirm that qemu:///system works, while qemu:///session not (as you have stated).
Maybe it worth to file a bug.

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Looks like there was already one open.