On Thu, 2007-06-21 at 20:41 +0800, Dong, Eddie wrote: > > 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%.
Yeah, you are probably right. I never quantified it. I just new PIT was 2x and clock was faster, so I assumed 2x. > > 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 ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
