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Home > Archive > Red Hat General > May 2004 > 2 Processors Show 4 on RedHat9
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2 Processors Show 4 on RedHat9
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| Hi there,
I have just installed RedHat9 on my Dell PowerEdge 2600 (2 processors). The
Linux kernel supports smp.
It very strange that the /proc/cpuinfo file contains 4 processors. And "top"
command shows 4 processors as well.
Buy two, get four. Am I lucky? Or will this cause performance problem?
Any idea would appreciated,
Ross
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| MisterJ 2004-01-23, 7:11 pm |
| Ross wrote:
quote:
> I have just installed RedHat9 on my Dell PowerEdge 2600 (2 processors). The
> Linux kernel supports smp.
> It very strange that the /proc/cpuinfo file contains 4 processors. And "top"
> command shows 4 processors as well.
Could it be that those 2 processors support Hyper Threading, and thus each
processor acts as 2 (virtual) processors?
If you like it, use it. If you don't, turn it of in the bios (don't know
if that's possible on this machine) or by giving the "noht" option to you
kernel.
MisterJ
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| On Wed, 03 Dec 2003 10:13:01 -0500, Ross wrote:
quote:
> Hi there,
> I have just installed RedHat9 on my Dell PowerEdge 2600 (2 processors).
> The Linux kernel supports smp.
> It very strange that the /proc/cpuinfo file contains 4 processors. And
> "top" command shows 4 processors as well.
> Buy two, get four. Am I lucky? Or will this cause performance problem? Any
> idea would appreciated,
> Ross
You have 2 Xeon processors supporting HT, what you are seeing is
normal
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| Andrew Jaffe 2004-01-23, 7:11 pm |
|
Hi-
nolo <nolo@nospamthankyouv.com> writes:quote:
> On Wed, 03 Dec 2003 10:13:01 -0500, Ross wrote:
>
>
> You have 2 Xeon processors supporting HT, what you are seeing is
> normal
Conversely, I have a dual Xeon dell running RH9, and it only sees 2
cpus. Any idea why? It is running the smp kernel, but /proc/cpuinfo and
top only see the two processors.
Any ideas?
Andrew
~> uname -a
Linux god 2.4.20-8smp #1 SMP Thu Mar 13 17:45:54 EST 2003 i686 i686 i386 GNU/Linux
~> cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) Xeon(TM) CPU 2.40GHz
stepping : 7
cpu MHz : 2392.762
cache size : 512 KB
physical id : 0
siblings : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
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
bogomips : 4771.02
processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) Xeon(TM) CPU 2.40GHz
stepping : 7
cpu MHz : 2392.762
cache size : 512 KB
physical id : 3
siblings : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
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
bogomips : 4784.12
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| My knowledge was far behind current technology. Now, I know "Hyper
Threading".
Thanks a bunch to you all.
Ross
"Ross" <Ross@nospam.com> wrote in message
news:IICdnXfHvNjiYFCiRVn-hg@magma.ca...quote:
> Hi there,
> I have just installed RedHat9 on my Dell PowerEdge 2600 (2 processors).
Thequote:
> Linux kernel supports smp.
> It very strange that the /proc/cpuinfo file contains 4 processors. And
"top"quote:
> command shows 4 processors as well.
> Buy two, get four. Am I lucky? Or will this cause performance problem?
> Any idea would appreciated,
> Ross
>
>
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| Andrew Spartz 2004-01-23, 7:11 pm |
| Andrew Jaffe <a.jaffe@imperial.ac.uk> wrote:
quote:
> Conversely, I have a dual Xeon dell running RH9, and it only sees 2
> cpus. Any idea why? It is running the smp kernel, but /proc/cpuinfo and
> top only see the two processors.
I would guess that your MB/BIOS does not support HT. That's what I have
now -- my 1.8P4 supports ht, but my Asus p4s333 MB does not. Hence no
ht for me.
ARS
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| If "hyper threading" is enabled in BIOS setup menu, Linux should detect
4 CPUs. If the hyper threading is disabled, it only know 2 physical CPUs.
Andrew Jaffe wrote:
> Hi-
>
> nolo <nolo@nospamthankyouv.com> writes:
>
>
>
> Conversely, I have a dual Xeon dell running RH9, and it only sees 2
> cpus. Any idea why? It is running the smp kernel, but /proc/cpuinfo and
> top only see the two processors.
>
> Any ideas?
>
> Andrew
>
> ~> uname -a
> Linux god 2.4.20-8smp #1 SMP Thu Mar 13 17:45:54 EST 2003 i686 i686 i386 GNU/Linux
>
> ~> cat /proc/cpuinfo
> processor : 0
> vendor_id : GenuineIntel
> cpu family : 15
> model : 2
> model name : Intel(R) Xeon(TM) CPU 2.40GHz
> stepping : 7
> cpu MHz : 2392.762
> cache size : 512 KB
> physical id : 0
> siblings : 1
> fdiv_bug : no
> hlt_bug : no
> f00f_bug : no
> coma_bug : no
> fpu : yes
> fpu_exception : yes
> cpuid level : 2
> 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
> bogomips : 4771.02
>
> processor : 1
> vendor_id : GenuineIntel
> cpu family : 15
> model : 2
> model name : Intel(R) Xeon(TM) CPU 2.40GHz
> stepping : 7
> cpu MHz : 2392.762
> cache size : 512 KB
> physical id : 3
> siblings : 1
> fdiv_bug : no
> hlt_bug : no
> f00f_bug : no
> coma_bug : no
> fpu : yes
> fpu_exception : yes
> cpuid level : 2
> 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
> bogomips : 4784.12
>
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