On Jan 8, 2008 5:05 AM, Rick Barnes linux@sitevision.com wrote:
Akemi Yagi wrote:
On Jan 8, 2008 4:51 AM, Rick Barnes linux@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-... (scroll down to tick_divider in the Feature Updates section)
Akemi