On Sat, 2019-04-06 at 20:26 -0400, Sam Varshavchik wrote:
Tom Horsley writes:
Here's a weird one I just noticed: I've been using a Windows 10 virtual machine to run my tax software. I've got it displayed in virt-viewer and all is well, then I close the virt-viewer window and leave the KVM running. About 5 minutes later I see a cpu suddenly pegged at 100%. I run top and see that qemu is the culprit. I start virt-viewer again, and it goes back to normal.
Anyone else seen this? Why would nobody looking at it make it go crazy I wonder?
Because you're using Microsoft Windows 10. Its built-in spyware and telemetry, that runs all the time and needs to report to Redmond, isn't cost- free and is pretty hard on the CPU.
True, however QEMU-KVM also consumes significant CPU even when the Windows guest is paused:
https://bugzilla.redhat.com/show_bug.cgi?id=1638289
poc