Re: [PATCH] x86_64: make amd quad core 8 socket system not be clustered_box v2

From: Yinghai Lu
Date: Tue Feb 26 2008 - 00:27:53 EST


On Mon, Feb 25, 2008 at 8:05 PM, Ravikiran Thirumalai <kiran@xxxxxxxxxxx> wrote:
> 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 :()
>
any good sign for APIC_clustered box? there is apicid between cpus
even all cpu are quadcore and fully populated?

YH
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