Re: cpuid : Hyper threading siblings: 16?

[Martin Steigerwald <Martin@lichtvoll.de>]

Am Donnerstag, 8. November 2012 schrieb Philip Ashmore:
> On 08/11/12 19:38, Martin Steigerwald wrote:
> > Am Donnerstag, 8. November 2012 schrieb Philip Ashmore:
> >> But cat /proc/cpuinfo says:
> >> ...
> >> processor       : 0
> >> vendor_id       : GenuineIntel
> >> cpu family      : 6
> >> model           : 42
> >> model name      : Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
> >> stepping        : 7
> >> microcode       : 0x28
> >> cpu MHz         : 2201.000
> >> cache size      : 6144 KB
> >> physical id     : 0
> >> siblings        : 8
> >> core id         : 0
> >> cpu cores       : 4
> >> ...
> >> 
> >> I'm sure the system has 4 cores or 8 hyper-threads.
> >> Am I reading it wrong?
> > 
> > Regarding the subject of you mail:
> > 
> > Thats in total 8 siblings.
> > 
> > So you divide 8 / 4 and get 2 siblings per core. I never seen any
> > hyperthreading with more than 2 siblings per core so far.
> > 
> > Ciao,
> 
> I guess I wasn't being clear: cpuid tells me I have 16 siblings:
> 
> $ cpuid
[…]
> Extended brand string: "      Intel(R) Core(TM) i7-2670QM CPU @
> 2.20GHz" CLFLUSH instruction cache line size: 8
> Initial APIC ID: 3
> Hyper threading siblings: 16
[…]

I think it is either making things up or getting some wrong information by 
BIOS.

For the dualcore CPU in this ThinkPad T520 it tells also 16:

Extended brand string: "       Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz"
CLFLUSH instruction cache line size: 8
Initial APIC ID: 3
Hyper threading siblings: 16


dmidecode got it right however:

merkaba:~> dmidecode | grep -i "Thread count"
        Thread Count: 4

So I think there is a bug in cpuid.

Ciao,
-- 
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
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