One virtual cpu missing (Dual Xeon system)

muflon · 06-24-2004, 03:43 AM

/proc/cpuinfo shows 3 cpus when in the past it has shown 4.

Code:

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 2
model name      : Intel(R) XEON(TM) CPU 2.20GHz
stepping        : 4
cpu MHz         : 2192.955
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        : 4377.80
 
processor       : 1
vendor_id       : GenuineIntel
cpu family      : 15
model           : 2
model name      : Intel(R) XEON(TM) CPU 2.20GHz
stepping        : 4
cpu MHz         : 2192.955
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        : 4377.80
 
processor       : 2
vendor_id       : GenuineIntel
cpu family      : 15
model           : 2
model name      : Intel(R) XEON(TM) CPU 2.20GHz
stepping        : 4
cpu MHz         : 2192.955
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        : 4377.80

1 cpu on physical id 0
2 cpus on physical id3

Is this software or hardware related?

Redhat 9
redhat kernel 2.4.20-31.9smp #1 SMP
gcc 3.2.2

finegan · 06-26-2004, 07:51 AM

That's just weird... probably hardware, what has BIOS got to say about HT enabling? Might want to load defaults and take it to a state of grace, and try a different kernel just to rule kernel out. That is strange!

Cheers,

Finegan

pixelbeat · 08-02-2004, 07:10 PM

I'm using my own kernel based on 2.4.20

Intermittently I get 3 or 4 of the following:

vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) Xeon(TM) CPU 2.66GHz
stepping : 7
cpu MHz : 2667.204
cache size : 512 KB
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 : 5324.80

I've a copy of /proc/kmsg showing the CPU registration.
A summary of which is:

<6>4 CPUs total
<4>Enabling the CPU's according to the ACPI table
<4>Intel MultiProcessor Specification v1.4
<4> Virtual Wire compatibility mode.
<4>Processors: 4
<4>Booting processor 2/6 eip 2000
<4>Not responding.
<4>CPU #6 not responding - cannot use it.
<4>Booting processor 2/7 eip 2000
<6>Initializing CPU#2
...

Electro · 08-03-2004, 12:06 AM

Check BIOS changes from your motherboard manufacture.

IMO, Hyperthreading is a freaking gimick. Two physical processor are always faster than one processor set for hyperthreading. Also four physical processors are always faster than two processors set for hyperthreading. AMD has showd us this already.