On 25 November 2013 04:20, Frantisek Hanzlik <franta@hanzlici.cz> wrote:

On Fedora 19/x86_64, Xeon 4cores/8threads, 8GB RAM I have in a VM
installed windows 2000 (full qemu cmdline see below). What is weird,
'top' on host show that all 4 threads load CPU at 100% each. On guest
are running only minimum processes and windows task manager show load
0-2%; virtual machine is almost idle. VM itself seems react well, its
responses are fine.

I've seen this behaviour before on Windows guests with incorrect HAL (non-ACPI) causing the guests to basically busy spin on the CPUs ...

I had to rebuild the box with an appropriate HAL to get it to behave sanely...

Incidentally your performance in that guest will always be fairly poor due to a lack of virtio drivers and windows 2000 has been out of support for a few years now ... you really should not be using it in general...