Re: A testing for KVM

I'm not sure if this affects the TSC theory or not, but note that the
host and guest have 250Hz PIT configured in the config.  E.g. both
kernels are programming the PIT to 250Hz, but guest is only
seeing 125Hz
ticks.  If I "fix" the lost interrupt to bring the ticks to a true
250Hz, wall-clock time runs at 2x.  Could it still be a TSC
virtualization problem under these conditions? (I dont know much about
TSC, so I just thought I would clarify this detail)

Yes, though I am not sure if it is 2X but anyway faster in guest.
We saw this in Xen but not that much. probably +20-30%.

From your observation, it looks like guest OS add back 100% 

lost ticks which is quit more than I observed in Xen. Probably it
has additional issue besides TSC. (I won't say it is a TSC
virtualization issue, but PIT virtualization issue :-(
Eddie

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