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Subject: Re: [hwloc-devel] Intel extended topology enumeration in x2APIC-supported processor
From: Brice Goglin (Brice.Goglin_at_[hidden])
Date: 2010-12-01 04:22:48


Hello Wei Lin,

The x86 indeed needs regular updates to support latest processors. But
this x86 backend is mostly only useful if you're using an operating
system that does not export topology information. If you're using Linux,
a recent kernel should already tell hwloc everything you need, and the
x86 backend will not be used at all. Do you actually see some wrong
lstopo output on such machines? FWIW, we use hwloc on many Westmere-EP
and Nehalem-EX machines without problem, and we know SGI has been using
it on large UV machines too.

Best regards,
Brice

Le 01/12/2010 10:07, Wei Lin a écrit :
>
> Hi, hwloc-devel
>
>
>
> I cannot find the code branch from "src/topology-x86.c "which can
> support for 32-bit APIC ID and CPUID leaf 0xb of Intel's new processors.
>
> So I think current hwLoc cannot support for latest Intel CPU with
> *x2APIC*.
>
>
>
> Linux kernel 2.6.30 or following version already supports this
> hardware feature
>
> and uses CPUID leaf 0xb to recognize the topology for more than 1024
> logical processors in SGI's super computer.
>
>
>
> I think hwloc could also support this.
>
>
>
> The following docs from Intel give details about x2APIC:
>
> http://www.intel.com/Assets/PDF/appnote/241618.pdf
>
> http://www.intel.com/Assets/pdf/manual/318148.pdf
>
> or <<Intel® 64 Architecture Processor Topology Enumeration>>
>
>
>
> Thanks
>
> Wei Lin
>
> 2010-12-1
>
>
>
>
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