Marcelo Tosatti wrote: > Another source of problems in this area is that the TSC_OFFSET is > initialized to represent zero at different times for VCPU0 (at boot) and > the remaining ones (at APIC_DM_INIT). > >
I added tsc sync in the guest bios some time ago, so this should be solved now. >> This will improve tsc quality for those machines, but we can't depend on >> it, since some machines don't have constant tsc. Further, I don't think >> really large machines can have constant tsc since clock distribution >> becomes difficult or impossible. >> > > As discussed earlier, in case the host kernel does not have the TSC > stable, it needs to enforce a state which the guest OS will not trust > the TSC. The easier way to do that is to fake a C3 state. However, QEMU > does not emulate IO port based wait. This appears to be the reason for > the high-CPU-usage-on-idle with Windows guests, fixed by disabling C3 > reporting on rombios (commit cb98751267c2d79f5674301ccac6c6b5c2e0c6b5 of > kvm-userspace). > > Oh. Can you point me at documentation for the io port wait thing? -- Any sufficiently difficult bug is indistinguishable from a feature. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
