Hi. I found out that disabling AMD Cool and Quiet from BIOS will remove the flood of these messages under Xen Dom0: If BIOS support for switching CPU frequencies is turned off, Linux kernel won't try to alter the frequency. My computer has Fedora 16, basic desktop computer. The hardware is old, and thus I haven't bothered to request features for this old hardware. Only problem with the hardware is, that XEN Hypervisor scheduler doesn't use HPET. I think hypervisor scheduler does busy looping, instead of using HALT instruction. This was a problem on last hot Summer, but now it is cold Autum. Without Xen Hypervisor on Linux kernel, I use "hpet=force". Linux Kernel finds out by the knowledge of old hardware, that HPET is propably there, even though ACPI doesn't advertice it. "hpet=force" was on XEN Hypervisor a few years ago, but the code has been removed. I don't know if it is coming back. I can test old hardware so that XEN hypervisor and DOM0 messages go into a serial cable. Not every day though. Regards, Marko Ristola -- xen mailing list xen@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/xen