I observed a similar behavior with a different application on a Windows host. The application is using the multimedia timer. In my case it seems that the timer is catching up the ticks missed during suspend to ram after resume. The timer thread performing the callbacks has high-priority on Windows and makes the host machine almost unusable for a certain time depending on the suspend duration. Maybe it is a similar situation here?
-- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1174654 Title: qemu-system-x86_64 takes 100% CPU after host machine resumed from suspend to ram Status in QEMU: Confirmed Status in qemu package in Ubuntu: Invalid Bug description: I have Windows XP SP3 inside qemu VM. All works fine in 12.10. But after upgraiding to 13.04 i have to restart the VM each time i resuming my host machine, because qemu process starts to take CPU cycles and OS inside VM is very slow and sluggish. However it's still controllable and could be shutdown by itself. According to the taskmgr any active process takes 99% CPU. It's not stuck on some single process. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1174654/+subscriptions