E7400 - i386 and AMD64
Pablo Armando
We have a new server with an Intel Core 2 Duo E7400. So only 2 CPU
exist.
When we run Debian lenny AMD64 on it, we see this output from /proc/cpuinfo:
# uname -a
Linux srv 2.6.26-2-amd64 #1 SMP Thu May 28 21:28:49 UTC 2009 x86_64
GNU/Linux
# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : unknown
stepping : 10
cpu MHz : 2666.608
cache size : 3072 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 4
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 13
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 pbe syscall nx lm
constant_tsc arch_perfmon pebs bts rep_good pni tm2 ssse3 lahf_lm
bogomips : 5336.90
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:
processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : unknown
stepping : 10
....
processor : 2
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : unknown
stepping : 10
...
processor : 3
vendor_id : GenuineIntel
cpu family : 6
model : 23
model name : unknown
stepping : 10
...
So it shows 4 CPU but we only have 2.
If we boot with Lenny i386 we see normal output (2 CPU's) and correct "model
name" identification.
Model name : Intel(R) Core(TM)2 CPU E7400 @ 2.80GHz
Should we use Debian amd64 here o i386? Why we see 4 CPU's when we only have
2 CPUs (Intel Core 2 Duo)? Is stable amd64 or it is not recommended for a
server setup?
Thanks in advance and sorry for my bad English.
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Dirk Neumann
"Pablo Armando" <parm...@express.com.ar> wrote:
> Hello,
>
> We have a new server with an Intel Core 2 Duo E7400. So only 2 CPU
> exist.
>
> When we run Debian lenny AMD64 on it, we see this output from /proc/cpuinfo:
>
> # uname -a
> Linux srv 2.6.26-2-amd64 #1 SMP Thu May 28 21:28:49 UTC 2009 x86_64
> GNU/Linux
>
> # cat /proc/cpuinfo
> 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 pbe syscall nx lm
^^
Your CPU supports HyperThreading, so you have 4 virtual cores.
> So it shows 4 CPU but we only have 2.
That's great. The more CPUs, the more you can do. Try a
# time make -j16
on your favourite reasonable big sourcecode and compare it with
deactivated ht.
>
> If we boot with Lenny i386 we see normal output (2 CPU's) and correct "model
> name" identification.
>
> Model name : Intel(R) Core(TM)2 CPU E7400 @ 2.80GHz
# cat /proc/cpuinfo
??
>
>
> Should we use Debian amd64 here o i386? Why we see 4 CPU's when we only have
> 2 CPUs (Intel Core 2 Duo)? Is stable amd64 or it is not recommended for a
> server setup?
amd64 should be fine for your server.
Dirk.
Kelly Harding
>>
>> # cat /proc/cpuinfo
>> 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 pbe syscall nx lm
> ^^
> Your CPU supports HyperThreading, so you have 4 virtual cores.
>
Thats odd, as the E7400 Core2Duo doesn't support HT according to
Intel's own site.
Unless the OP got the model name of the CPU wrong?
The E7xxx chips are the lower cost version of the E8xxx chips, with
less cache, slower
FSB and no support for Vt.
None of the Core2Duo chips to my knoledge support HT. Only Xeons and
i7 chips do of the Core
architecture IIRC.
Kelly
Sven Joachim
> 2009/7/10 Dirk Neumann <dirkn...@gmx.ch>:
>> On Fri, 10 Jul 2009 15:15:27 -0300
>> "Pablo Armando" <parm...@express.com.ar> wrote:
>
>>>
>>> # cat /proc/cpuinfo
>>> 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 pbe syscall nx lm
>> � � � � � � � � � � � � � � � � � � � � � � � � � � � ^^
>> Your CPU supports HyperThreading, so you have 4 virtual cores.
>>
>
> Thats odd, as the E7400 Core2Duo doesn't support HT according to
> Intel's own site.
The ht flag just means that the CPU reports it, and multicores always do
that. So this is not the answer to the OP's odd problem.
Sven
lee
> Should we use Debian amd64 here o i386? Why we see 4 CPU's when we only have
> 2 CPUs (Intel Core 2 Duo)? Is stable amd64 or it is not recommended for a
> server setup?
You'll want to use amd64, it's stable. Even before there was a stable
version, I've been running it on a server with dual Opterons and have
never had a problem with it. Besides, I have an E8400, and that CPU
seems to be particularly slow in 32bit mode and when running a piece
of 32bit software in the amd64 environment. I am somewhat disappointed
with the performance, even overclocked to 3.46GHz.
Did you use any weird kernel settings when you made the kernel for
your server? Did you try an older (like 2.6.24) or a newer kernel?
I think you should see only 2 CPUs, as you have 2. But I had always
set the max. number of CPUs to 2 for my kernels, so I wouldn't see any
more than 2 anyway. Maybe I should increase the limit and see what
happens. Maybe I get some CPUs for free ;)
Pablo Armando
-----Mensaje original-----
De: lee [mailto:l...@yun.yagibdah.de]
Enviado el: Sábado, 11 de Julio de 2009 03:13 p.m.
Para: debia...@lists.debian.org
Asunto: Re: E7400 - i386 and AMD64
>Did you use any weird kernel settings when you made the kernel for
>your server? Did you try an older (like 2.6.24) or a newer kernel?
We only use standard kernels from debian distribution (without recompiling
them).