Kai Schaetzl wrote on Sun, 03 Aug 2008 16:31:19 +0200: > Actually, not the latest kernel. The CentOS xen boot (hypervisor) kernel > /xen.gz-2.6.18-92.1.6.el5 (and maybe earlier) ones calculates the frequency > correct, the Xen 3.2 boot kernel (xen.gz-3.2) from the Xen 3.2 package > offered at xen.org does not. Might there be a kernel parameter or other > measure that could correct this? After some more research I have found the correct incantation for this. The CentOS/RH kernels seem to have this enabled by default, the kernels from xen.org have to be "enabled" with a command-line option to the hypervisor- kernel (not the CentOS kernel). kernel /xen.gz-3.2 cpufreq=dom0-kernel I'm getting now correct readings of the frequencies. And scaling up on demand works. At least in dom0. I'm not so sure if it works for domUs as well. A quick test showed no ondemand scaling in dom0 when running a cpu-intensive task in a domU. Anyone has more experience with this? Kai -- Kai Schätzl, Berlin, Germany Get your web at Conactive Internet Services: http://www.conactive.com