Amit Shah wrote: > > On Wednesday 19 December 2007 21:02:06 Glauber de Oliveira Costa wrote: > > On Dec 19, 2007 12:27 PM, Avi Kivity <[EMAIL PROTECTED]> wrote: > > > Ingo Molnar wrote: > > > > * Avi Kivity <[EMAIL PROTECTED]> wrote: > > > >> Avi Kivity wrote: > > > >>> Testing shows wrmsr and rdtsc function normally. > > > >>> > > > >>> I'll try pinning the vcpus to cpus and see if that helps. > > > >> > > > >> It does. > > > > > > > > do we let the guest read the physical CPU's TSC? That would be > trouble. > > > > > > vmx (and svm) allow us to add an offset to the physical tsc. We > set it > > > on startup to -tsc (so that an rdtsc on boot would return 0), and > > > massage it on vcpu migration so that guest rdtsc is monotonic. > > > > > > The net effect is that tsc on a vcpu can experience large forward > jumps > > > and changes in rate, but no negative jumps. > > > > Changes in rate does not sound good. It's possibly what's screwing up > > my paravirt clock implementation in smp. > > Do you mean in the case of VM migration, or just starting them on a single > host? > It's the cpu preemption stuff on local host and not VM migration > > > Since the host updates guest time prior to putting vcpu to run, two > > vcpus that start running at different times will have different system > > values. > > > > Now if the vcpu that started running later probes the time first, > > we'll se the time going backwards. A constant tsc rate is the only way > > around > > my limited mind sees around the problem (besides, obviously, _not_ > > making the system time per-vcpu). > > ------------------------------------------------------------------------- > SF.Net email is sponsored by: > Check out the new SourceForge.net Marketplace. > It's the best place to buy or sell services > for just about anything Open Source. > http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace > _______________________________________________ > kvm-devel mailing list > kvm-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/kvm-devel >
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