On Wed, Aug 20, 2008 at 5:37 AM, Michael Ekstrand <michael at elehack.net> wrote: > "Akemi Yagi" <amyagi at gmail.com> writes: >> I understand you built a 100Hz kernel, but *just in case*, you might >> want to try CentOS-supplied 100Hz kernel (kernel-vm) available from: >> >> http://people.centos.org/tru/kernel-vm/ > > Just tried it, and it doesn't seem to work. I used the following > parameters: > > nosmp noapic nolapic noacpi clocksource=pit > >> Also, enable time sync with host if that has not been done. > > Already done, and was active throughout the problems described above. > > I seem to remember seeing somewhere or another something about a > different set of timing devices available on 64-bit vs. 32-bit. cat /sys/devices/system/clocksource/clocksource0/available_clocksource will show you available options. It is different between 32-bit and 64-bit. > was previously using 32-bit Debian Etch as the host OS on this same > hardware with an upgraded (2.6.22) kernel, I had no noticable timing > problems on the FreeBSD guest (didn't run Linux guests enough to notice > anything). After switching to 64-bit CentOS host OS, the FreeBSD guest > clock started running fast, but it responded to adjustments and keeps in > line with the setup described above. Is it possible that running the > 64-bit host environment is what is causing my problems? Are there host > options I can tweak to try to improve the situation? On the *host* side, you can try disabling power management and other things. For example: apm=off acpi=off noapic Akemi > - Michael >