Messages in this thread | | | Date | Mon, 25 Feb 2008 20:05:41 -0800 | From | Ravikiran Thirumalai <> | Subject | Re: [PATCH] x86_64: make amd quad core 8 socket system not be clustered_box v2 |
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On Tue, Feb 26, 2008 at 04:46:25AM +0100, Andi Kleen wrote: >> I don't quite understand the purpose of the patch to begin with. Looking at >> the current x86 git tree, apic_is_clustered_box is used only to determine if >> tsc is synchronized on the platform. The AMD docs imply that TSC's are not >> guaranteed to be synced across cores between nodes -- Opteron BKDG for >> family 10h, Section 2.9.4: > >After long discussions with AMD they determined the CPUID flag >for sync RDTSC will imply synchronization between nodes.
Ah!
> >If you can't support that in your hardware you're supposed >to clear it.
Hmm! How would a hardware vendor do that? That doesn't seem to be clear in the BKDG. (Well, this is the problem with undocumented features :()
Thanks, Kiran
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