On Jan 8, 2008 5:05 AM, Rick Barnes <linux at sitevision.com> wrote: > > Akemi Yagi wrote: > > On Jan 8, 2008 4:51 AM, Rick Barnes <linux at sitevision.com> wrote: > >> Jack Bailey wrote: > >>> These domains are fully virtualized and set up identically, except > >>> "badclock" is allocated two processors versus one processor for > >>> "goodclock". DomU's clock is running normally. > >>> > >>> Anyone know what's going or know how to fix it? > >> This is a known issue that has come up on this list a lot. > >> > >> For C5.1 see the first known issue: > >> > >> http://wiki.centos.org/Manuals/ReleaseNotes/CentOS5.1/ > >> > >> Rick > > > > Please note that the clock rate issue in that description applies to > > non-xen kernels. xen kernels are set to 250Hz by default. > > "With this option you can reduce the clock rate from the default of > 1000HZ to 100HZ which is desirable in a virtual machine." > > If it does not apply to xen then this should be made more clear. > > Rick I think it is a good idea to add a note about xen kernels. But this is noted in the upstream Release Notes where the tick divider option is mentioned: "Note that the virtualized kernel does not support multiple timer rates on guests. dom0 uses a fixed timing rate set across all guests; this reduces the load that multiple tick rates could cause." http://www.centos.org/docs/5/html/release-notes/as-x86/RELEASE-NOTES-U1-x86-en.html (scroll down to tick_divider in the Feature Updates section) Akemi