Messages in this thread | | | Subject | Re: [PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs | From | john stultz <> | Date | Mon, 19 Sep 2005 12:42:16 -0700 |
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On Mon, 2005-09-19 at 21:31 +0200, Andi Kleen wrote: > On Mon, Sep 19, 2005 at 12:16:43PM -0700, john stultz wrote: > > This patch should resolve the issue seen in bugme bug #5105, where it > > is assumed that dualcore x86_64 systems have synced TSCs. This is not > > the case, and alternate timesources should be used instead. > > > I asked AMD some time ago and they told me it was synchronized. > The TSC on K8 is C state invariant, but not P state invariant, > but P states always happen synchronized on dual cores. > > So I'm not quite convinced of your explanation yet.
Would a litter userspace test checking the TSC synchronization maybe shed additional light on the issue?
thanks -john
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