[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] RE: Live migration fails due to c/s 20627
Dan Magenheimer wrote on Tue, 15 Dec 2009 at 09:08:40: > > As Jeremy has pointed out, the guest OS already has > other mechanisms to provide this information, and > as Jun has pointed out, the non-rdtscp mechanism (lsl > on Linux) may even be faster. Windows does not even > provide TSC_AUX, so it definitely has other ways to > obtain node/cpu info. And, as I've said before, > the node/cpu info provided by Linux in TSC_AUX is > wrong anyway (except in very constrained environments > such as where the admin has pinned vcpus to pcpus). I think we should distinguish architectural support and Linux-specific issues. We need to enable RDSTCP support in HVM if user apps want to use it. If we want the Linux or other kernel to stop using TSC_AUX, we can mask off the feature in CPUID. Access to the MSR should result in #GP in the guest if the feature is not advertized. BTW, I'm hearing that the max TSC difference among CPUs is less than 10 cycles or so (virtually 0) at least Intel-based machines (except limited ones with known issues), so probably such pinning should not be required because vcpu migration should take more than. Jun ___ Intel Open Source Technology Center _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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