Re: SMP hyperthreading and bi-processors
On Thu, Feb 16, 2006 at 07:12:44PM +0100, sebastien.prouff wrote:
> Good morning/afternoon,
>
> I have a problem on a bi-Xeon Server.
> I just installed (two days ago) the debian sarge for AMD64.
> The server is a bi-Xeon with hyperthreading.
> So, I have to see 4 processors in /proc/cpuinfo (that what I
> understood on various forums...) and I only see 2 processors.
>
> THis is the result of /proc/cpuinfo.
>
> Djak:/usr/src/kernel-headers-2.6.8-11-em64t-p4-smp# cat
> /proc/cpuinfo
> processor : 0
> vendor_id : GenuineIntel
> cpu family : 15
> model : 4
> model name : Intel(R) Xeon(TM) CPU 3.20GHz
> stepping : 3
> cpu MHz : 3200.253
> cache size : 0 KB
> physical id : 0
> siblings : 1
> fpu : yes
> fpu_exception : yes
> cpuid level : 3
> wp : yes
> flags : fpu vme de pse tsc msr pae mce cx8 apic sep
> mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2
> ss ht tm syscall nx lm pni monitor ds_cpl cid cmpxchg16b
> bogomips : 6324.22
> clflush size : 64
> cache_alignment : 128
> address sizes : 36 bits physical, 48 bits virtual
> power management:
>
> processor : 1
> vendor_id : GenuineIntel
> cpu family : 15
> model : 4
> model name : Intel(R) Xeon(TM) CPU 3.20GHz
> stepping : 3
> cpu MHz : 3200.253
> cache size : 0 KB
> physical id : 3
> siblings : 1
> fpu : yes
> fpu_exception : yes
> cpuid level : 5
> wp : yes
> flags : fpu vme de pse tsc msr pae mce cx8 apic sep
> mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2
> ss ht tm syscall nx lm pni monitor ds_cpl cid cmpxchg16b
> bogomips : 6389.76
> clflush size : 64
> cache_alignment : 128
> address sizes : 36 bits physical, 48 bits virtual
> power management:
>
> So, instead of 4 results, I have just two results.
> - As you can see, there is the flags ht activated
> - the physical_id number is different so it is two different
> physical processor.
>
> This is my kernel :
> Linux Djak 2.6.8-11-em64t-p4-smp #1 SMP Mon Oct 3 00:07:51
> CEST 2005 x86_64 GNU/Linux
>
> As I download the header for this kernel, I try to see with a
> make menuconfig is something go wrong.
> Well, I did not see any problem, the processor type is EM64T
> with SMP activated up to 8 processors.
>
> So please help, because I'm stick
> I am waiting for your ideas.
Is hyperthreading disabled in the BIOS perhaps? Many servers ship that
way since in some cases hyperthreading hurts performance rather than
help it.
Len Sorensen
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