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Date:      Tue, 21 Sep 2010 20:52:31 +0300
From:      Andriy Gapon <avg@freebsd.org>
To:        Jung-uk Kim <jkim@freebsd.org>
Cc:        jeff@freebsd.org, freebsd-stable@freebsd.org
Subject:   Re: 8.1-PRERELEASE: CPU packages not detected correctly
Message-ID:  <4C98F0DF.1000801@freebsd.org>
In-Reply-To: <4C7F5F90.3030407@icyb.net.ua>
References:  <201007141414.o6EEEUx9014690@lurza.secnetix.de> <4C77F6D6.9020402@icyb.net.ua> <201008271536.08773.jkim@FreeBSD.org> <201009011426.26111.jkim@FreeBSD.org> <4C7F5F90.3030407@icyb.net.ua>

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on 02/09/2010 11:25 Andriy Gapon said the following:
> on 01/09/2010 21:26 Jung-uk Kim said the following:
>> On Friday 27 August 2010 03:36 pm, Jung-uk Kim wrote:
>>> [3] AMD is working on an SMT-capable CPU (code-named Bulldozer) and
>>> my patch won't work on them.  If anyone has a Bulldozer sample,
>>> please look into it.
>>
>> I checked AMD website today and found out a new CPUID Spec. Rev. 2.34 
>> was just released:
>>
>> http://support.amd.com/us/Embedded_TechDocs/25481.pdf
>>
>> They have added CPUID 0x8000001d and 0x8000001e to detect topology, it 
>> seems.  Also, CPUID 0x80000001 %ecx bit 22 (TopologyExtensions) tells 
>> you whether the above CPUID functions are supported.
>>
>> Interesting...
> 
> Yeah, I've heard that they are adding SMT capabilities in "Bulldozer"
> processors, so I guess they have to change CPU topology detection indicators.

The above comment by me is almost nonsense :)
I looked at the document with better attention and I think that what the new way
does is better/provides proper support for discovering non-uniform topologies
based on APIC IDs of the cores.

BTW, I am reading that AMD Bulldozer CPU package will consist of modules, which in
turn will consist of cores.  When a "core" would be something in between current
notion of core and current notion of hardware thread (SMT/HTT/whatever).
The Bulldozer cores will have independent arithmetic units and L1 caches, but
shared FPU, L2, fetch+decode and some other elements; L3 cache is per package
(shared by all "modules").

-- 
Andriy Gapon



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