Messages in this thread | | | Date | Mon, 19 Sep 2005 21:49:34 +0200 | From | Andi Kleen <> | Subject | Re: [discuss] Re: [PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs |
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On Mon, Sep 19, 2005 at 12:42:16PM -0700, john stultz wrote: > 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?
Sure you can try it.
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