Hi,

I am running Red Hat 2.4.18-14smp and when I run top or cat /proc/cpuinfo it shows I have 4 cpu's installed on my system. Which only has two real Xeon processors. And they are not duo core processors.

mycauldron

It would show hyperthreading if you have that enabled.

If you look at the number of reported cores vs. the number of different core IDs, you can tell whether the reported units represent hyperthreading.

I can't tell from this information. They are not Duo core so hyper threading makes sense. But I can't tell from this report if they are enabled or not.

If I read this correctly, then the below information states I only have one CPU in this system. And Hyperthreading is causing me to see 4.
Thanks,
mycauldron

cat /proc/cpuinfo

processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) Xeon(TM) CPU 3.06GHz
stepping : 9
cpu MHz : 3066.839
cache size : 512 KB
Physical processor ID : 0
Number of siblings : 2
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 : 6093.21

processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) Xeon(TM) CPU 3.06GHz
stepping : 9
cpu MHz : 3066.839
cache size : 512 KB
Physical processor ID : 0
Number of siblings : 2
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 : 6127.62

processor : 2
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) Xeon(TM) CPU 3.06GHz
stepping : 9
cpu MHz : 3066.839
cache size : 512 KB
Physical processor ID : 0
Number of siblings : 2
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 : 6127.62

processor : 3
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) Xeon(TM) CPU 3.06GHz
stepping : 9
cpu MHz : 3066.839
cache size : 512 KB
Physical processor ID : 0
Number of siblings : 2
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 : 6127.62

Looks like HT to me, HT is shown as a flag, and the "Physical processor ID" is all 0, for all 4, so I would say its safe to assume they are one physical CPU, and HT is giving you 4 virtual cores, if it wasn't enabled, you should only see one.

I don't understand that output. Only one physical ID, number of siblings=2, but four logical CPU's. From what I thought I understood, that doesn't make sense.

I don't think hyperthreading can more than double the number of logical CPU's, so something else also doubled it:

Two physical CPU's? But there is only one physical ID?

Dual core as well as hyperthreaded? But you seem sure it isn't dual core and that info says nothing about dual core.

I want to thank you SciYro & johnfine for the information it makes more sense now. Not as clear as I would like but it will help with inventory.

I can only assume as you say that something in Red Hat 8 is giving me the error as Red Hat 10 does not show the same thing.

I see the HT flag. And to answer johnsfine I am sure these systems are single processor systems. To date I don't duo core's have passed 2.8ghz and all these systems I installed over a year ago.

I know for sure that this system has two Xeon 3ghz processors..

cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Xeon(TM) CPU 3.00GHz
stepping : 3
cpu MHz : 3001.014
cache size : 0 KB
Physical processor ID : 0
Number of siblings : 2
flags : ht tm

processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Xeon(TM) CPU 3.00GHz
stepping : 3
cpu MHz : 3001.014
cache size : 0 KB
Physical processor ID : 379276962
Number of siblings : 2
flags : ht tm

processor : 2
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Xeon(TM) CPU 3.00GHz
stepping : 3
cpu MHz : 3001.014
cache size : 0 KB
Physical processor ID : 3014660
Number of siblings : 2
flags : ht tm

processor : 3
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Xeon(TM) CPU 3.00GHz
stepping : 3
cpu MHz : 3001.014
cache size : 0 KB
Physical processor ID : 0
Number of siblings : 2
flags : ht tm

========================

On a duo core system running Red Hat 10, Linux 2.6.9-42.0.0.0.1.ELsmp
Installed is one Intel Dual-Core Xeon 5140 / 2.33 GHz processor

cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Xeon(R) CPU 5140 @ 2.33GHz
stepping : 6
cpu MHz : 2327.585
cache size : 4096 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 2
flags : ht

processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Xeon(R) CPU 5140 @ 2.33GHz
stepping : 6
cpu MHz : 2327.585
cache size : 4096 KB
physical id : 0
siblings : 2
core id : 1
cpu cores : 2
flags : ht

HT is one of those things that's easy to miss and that's why I added recognition of it in collectl when you choose to look at cpu performance - http://collectl.sourceforge.net/
-mark