I just ran into what I think is the same issue. Windows 10 VM controlled from virt-manager using ~30% CPU while paused.
I'm attaching the output of pidstat -p $(pidof qemu-system-x86_64) -T ALL -rtuw 5 5 and the first thousand lines of strace -rT -ff -f -o paused-but-busy -p $(pidof qemu-system-x86_64) that you requested from the other reporter. As a non-expert, the repeated calls to ioctl(10, KVM_IRQ_LINE_STATUS, ...)+ppoll() timeout seem suggestive to me. Note: I'm omitting strace for all threads except the one consuming the CPU, since they each contain a single futex() call. If you'd like to see the futex addr/val, let me know. Thanks for investigating, Kevin Full disclosure: I'm using Debian rather than Ubuntu. If you'd like me to repro using the Ubuntu package versions (or on a fully Ubuntu system) I can give it a shot. Currently using qemu-system-x86 1:5.0-5, libvirt 6.0.0-6, and virt-manager 1:2.2.1-4. ** Attachment added: "strace from high-CPU thread of paused Windows 10 VM" https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1851062/+attachment/5386879/+files/qemu-high-cpu.strace -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1851062 Title: Qemu using CPU even when the VM is paused To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1851062/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
