3 Intel i7-2600 CPU cores missing

**melal** · 19th August 2012, 09:13 AM

I have Intel i7-2600 CPU. According to specification from Intel this CPU has 4 cores and 8 threads. But my Fedora 16 detects 1 core only, thus 3 cores still missing permanently. Some more details:

uname -a

Code:

Linux hostname 3.4.7-1.fc16.i686.PAE #1 SMP Mon Jul 30 16:45:15 UTC 2012 i686 i686 i386 GNU/Linux

lscpu

Code:

Architecture:          i686
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                1
On-line CPU(s) list:   0
Thread(s) per core:    1
Core(s) per socket:    1
Socket(s):             1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 42
Stepping:              7
CPU MHz:               3400.059
BogoMIPS:              6800.11
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              8192K

cat /proc/cpuinfo

Code:

processor	: 0
vendor_id	: GenuineIntel
cpu family	: 6
model		: 42
model name	: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz
stepping	: 7
microcode	: 0x28
cpu MHz		: 3400.059
cache size	: 8192 KB
physical id	: 0
siblings	: 1
core id		: 0
cpu cores	: 1
apicid		: 0
initial apicid	: 0
fdiv_bug	: no
hlt_bug		: no
f00f_bug	: no
coma_bug	: no
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 nx rdtscp lm constant_tsc up arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx lahf_lm ida arat epb xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority ept vpid
bogomips	: 6800.11
clflush size	: 64
cache_alignment	: 64
address sizes	: 36 bits physical, 48 bits virtual
power management:

cat /proc/cmdline

Code:

BOOT_IMAGE=/boot/vmlinuz-3.4.7-1.fc16.i686.PAE root=UUID=c3a20a9c-df77-4705-8c96-4129cc002140 ro rd.md=0 rd.lvm=0 rd.dm=0 KEYTABLE=us quiet SYSFONT=latarcyrheb-sun16 rhgb rd.luks=0 LANG=en_US.UTF-8

dmesg: dmesg.txt

Please, advise. Thank you very much in advance!

**george_toolan** · 19th August 2012, 10:25 AM

What kind of motherboard is this and did you install the latest BIOS?

ACPI: no DMI BIOS year, acpi=force is required to enable ACPI
ACPI: Disabling ACPI support

weird, boot CPU (#0) not listed by the BIOS.
SMP motherboard not detected.

Try to boot with acpi=force or similar boot options. If you succeed it should look something like this (which is only a 2500k)

Code:

Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0-3
Thread(s) per core:    1
Core(s) per socket:    4
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 42
Stepping:              7
CPU MHz:               1600.000
BogoMIPS:              6584.73
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              6144K
NUMA node0 CPU(s):     0-3

**melal** · 19th August 2012, 10:55 AM

Dear george_toolan, thank you so much for you early reply!
I'll try tomorrow to boot with acpi=force option and post report in details. My motherboard is real headache under Fedora 16. It's Intel Original DH77EB Desktop Board. Due to well known Fedora bug with mdadm and dracut it's impossible neither reboot nor shutdown the server by ssh and I have to ask everytime staff who has physical access to server help to reset the server manually. Also it has multiple *BAD*gran_size messages and so on, but I'm trying now to solve this big problem - "Intel DH77EB under Fedora 16" step by step. OK, tomorrow I'll check if the motherboard has latest BIOS, boot it with acpi=force option and let you know results about.

**weitjong** · 19th August 2012, 03:05 PM

Definitely something is wrong with your system. I have a i7-2600K which is quite similar to yours. Both Fedora 16 and 17 "see" that I have 8 CPUs machine (4 cores with HT).

Code:

$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                8
On-line CPU(s) list:   0-7
Thread(s) per core:    2
Core(s) per socket:    4
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 42
Stepping:              7
CPU MHz:               1600.000
BogoMIPS:              6799.90
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              8192K
NUMA node0 CPU(s):     0-7

---------- Post added at 10:05 PM ---------- Previous post was at 10:02 PM ----------

I am not really able to point out what is wrong with your system though. Just want to show you what the output should like.

**MauserM98** · 19th August 2012, 10:02 PM

-----------------
Message deleted. Just rubbish.

**melal** · 20th August 2012, 07:38 AM

Thank SO MUCH for significant HELP, guys!
The problem is solved by adding acpi=force to kernel cmdline at /boot/grub2/grub.cfg and /etc/default/grub. It seems something is wrong with Intel DH77EB motherboard as I see in dmesg now:

Code:

[    0.000000] ACPI: no DMI BIOS year, acpi=force is required to enable ACPI
[    0.000000] ACPI: acpi=force override

instead of

Code:

[    0.000000] ACPI: no DMI BIOS year, acpi=force is required to enable ACPI
[    0.000000] ACPI: Disabling ACPI support

I consider there is a some imperfection in Intel DH77EB motherboard which requires acpi forcing.

Now I see:

lscpu

Code:

Architecture:          i686
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                8
On-line CPU(s) list:   0-7
Thread(s) per core:    2
Core(s) per socket:    4
Socket(s):             1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 42
Stepping:              7
CPU MHz:               1600.000
BogoMIPS:              6800.41
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              8192K

cat /proc/cmdline

Code:

BOOT_IMAGE=/boot/vmlinuz-3.4.9-1.fc16.i686.PAE root=UUID=c3a20a9c-df77-4705-8c96-4129cc002140 ro rd.md=0 rd.lvm=0 rd.dm=0 acpi=force KEYTABLE=us quiet SYSFONT=latarcyrheb-sun16 rhgb rd.luks=0 LANG=en_US.UTF-8

At the same time acpi forcing solved another problem - the server now has no "hangs" at reboot and shutdown.

Finally was solved one more CPU problem. There was the line in dmesg before:

Code:

[    1.190027] p4-clockmod: Warning: EST-capable CPU detected. The acpi-cpufreq module offers voltage scaling in addition to frequency scaling. You should use that instead of p4-clockmod, if possible.

This CPU voltage scaling in addition to frequency scaling issue was solved by creating of file /etc/modprobe.d/blacklist-p4-clockmod.conf with content:

Code:

blacklist p4-clockmod

and adding to /etc/rc.d/rc.local the line:

Code:

modprobe acpi-cpufreq

In other words the kernel module p4-clockmod has been blacklisted and instead of this module another acpi-cpufreq kernel module has been loaded as more suitable for CPU with EST-capability as it follows from dmesg.

dmesg: dmesg_new.txt

Thanks again to everybody and to george_toolan especially for valuable help!

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