[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] write_tsc in a PV domain?
> No, I don't think this is true. An enterprise app that binds processes > to fixed physical processors on a physical machine can make > assumptions about the results of rdtsc that aren't valid when > the vcpus can skip between pcpus. Further, like Linux itself, They rarely make the right assumptions > applications may test assumptions about tsc at startup that are > assumed to remain valid for the life of the app, which is > perfectly reasonable on a physical machine No it isn't because of things like suspend/resume. > True, but any app that tries to run on a NUMA machine without > being aware of the idiosyncracies of a NUMA machine probably > has worse problems to deal with than tsc sync. Further, there Disagree - this is true if your NUMA factor is large but quite a few machines today are "vaguely NUMA" - the NUMA factor is low enough the app doesn't need to care. Anyway you don't need NUMA to see TSC skew between cores. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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