On 11/08/2010 02:22 PM, Sven Lankes wrote: > On Mon, Nov 08, 2010 at 12:38:22PM +0000, Daniel P. Berrange wrote: > >> Try adding divider=10 to the kernel boot command line for the guest. >> This will make it use a 100HZ tick rate, instead of 1000HZ, lowering the >> background idle load on the host. I doubt it accounts for 20%, but it is >> always worth doing for RHEL5 kernels since they don't have tickless mode. > > I was seeing 10 - 15% cpu for the kvm process too. After adding > divider=10 this dropped to 1%. >
The fact that the guest needs special kernel parameters to run properly doesn't look right to me. Is there no way for KVM to handle this correctly? Also I just imported this VM from my old Fedora 11 system on the new Fedora 14 install and there I didn't see this behavior. BTW this might or might not be related to a general problem with the kernel in Fedora 14: https://bugzilla.redhat.com/show_bug.cgi?id=650934 https://bugzilla.redhat.com/show_bug.cgi?id=635813 Anyway, I'm off trying to boot my system with nohz=off and then add the divider thing to the guest to see if that has any impact. Regards, Dennis _______________________________________________ virt mailing list [email protected] https://admin.fedoraproject.org/mailman/listinfo/virt
