Hi,

My OS is RedHat Enterprise Linux 5, kernel is 2.6.18-8.el5. But it recognized my 2.1GHz Quad Core Barcelona CPU as 1.3GHz Quad Core Barcelona CPU. Do you know why? How to fix this problem?

BTW, the BIOS can recognize 2.1GHz Quad Core Barcelona CPU.

Thanks,

first I would look at what the system sees..

yum install lshw
lshw -C processor

or

cat /proc/cpuinfo

or

dmidecode -t processor

cat /proc/cpuinfo
processor : 0
vendor_id : AuthenticAMD
cpu family : 16
model : 2
model name : Quad-Core AMD Opteron(tm) Processor 2352
stepping : 3
cpu MHz : 1300.000
cache size : 512 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow constant_tsc pni monitor cx16 lahf_lm cmp_legacy svm cr8_legacy
bogomips : 4205.96
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc [6] [7] [8]

processor : 1
vendor_id : AuthenticAMD
cpu family : 16
model : 2
model name : Quad-Core AMD Opteron(tm) Processor 2352
stepping : 3
cpu MHz : 1300.000
cache size : 512 KB
physical id : 4
siblings : 4
core id : 0
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow constant_tsc pni monitor cx16 lahf_lm cmp_legacy svm cr8_legacy
bogomips : 4199.67
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc [6] [7] [8]

processor : 2
vendor_id : AuthenticAMD
cpu family : 16
model : 2
model name : Quad-Core AMD Opteron(tm) Processor 2352
stepping : 3
cpu MHz : 1300.000
cache size : 512 KB
physical id : 0
siblings : 4
core id : 1
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow constant_tsc pni monitor cx16 lahf_lm cmp_legacy svm cr8_legacy
bogomips : 4199.57
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc [6] [7] [8]

processor : 3
vendor_id : AuthenticAMD
cpu family : 16
model : 2
model name : Quad-Core AMD Opteron(tm) Processor 2352
stepping : 3
cpu MHz : 1300.000
cache size : 512 KB
physical id : 4
siblings : 4
core id : 1
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow constant_tsc pni monitor cx16 lahf_lm cmp_legacy svm cr8_legacy
bogomips : 4199.56
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc [6] [7] [8]

processor : 4
vendor_id : AuthenticAMD
cpu family : 16
model : 2
model name : Quad-Core AMD Opteron(tm) Processor 2352
stepping : 3
cpu MHz : 1300.000
cache size : 512 KB
physical id : 0
siblings : 4
core id : 2
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow constant_tsc pni monitor cx16 lahf_lm cmp_legacy svm cr8_legacy
bogomips : 4199.57
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc [6] [7] [8]

processor : 5
vendor_id : AuthenticAMD
cpu family : 16
model : 2
model name : Quad-Core AMD Opteron(tm) Processor 2352
stepping : 3
cpu MHz : 1300.000
cache size : 512 KB
physical id : 4
siblings : 4
core id : 2
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow constant_tsc pni monitor cx16 lahf_lm cmp_legacy svm cr8_legacy
bogomips : 4199.57
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc [6] [7] [8]

processor : 6
vendor_id : AuthenticAMD
cpu family : 16
model : 2
model name : Quad-Core AMD Opteron(tm) Processor 2352
stepping : 3
cpu MHz : 1300.000
cache size : 512 KB
physical id : 0
siblings : 4
core id : 3
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow constant_tsc pni monitor cx16 lahf_lm cmp_legacy svm cr8_legacy
bogomips : 4199.56
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc [6] [7] [8]

processor : 7
vendor_id : AuthenticAMD
cpu family : 16
model : 2
model name : Quad-Core AMD Opteron(tm) Processor 2352
stepping : 3
cpu MHz : 1300.000
cache size : 512 KB
physical id : 4
siblings : 4
core id : 3
cpu cores : 4
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow constant_tsc pni monitor cx16 lahf_lm cmp_legacy svm cr8_legacy
bogomips : 4199.56
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc [6] [7] [8]



dmidecode -t processor

# dmidecode 2.7
SMBIOS 2.6 present.

Handle 0x000F, DMI type 4, 35 bytes.
Processor Information
Socket Designation: CPU0-Socket 1207
Type: Central Processor
Family: <OUT OF SPEC>
Manufacturer: AuthenticAMD
ID: 23 0F 00 00 01 03 00 00
Version: AMD Opteron
Voltage: 1.2 V
External Clock: 200 MHz
Max Speed: 2100 MHz
Current Speed: 2100 MHz
Status: Populated, Enabled
Upgrade: <OUT OF SPEC>
L1 Cache Handle: 0x0009
L2 Cache Handle: 0x000A
L3 Cache Handle: 0x000B
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified

Handle 0x0010, DMI type 4, 35 bytes.
Processor Information
Socket Designation: CPU1-Socket 1207
Type: Central Processor
Family: <OUT OF SPEC>
Manufacturer: AuthenticAMD
ID: 23 0F 00 00 01 03 00 00
Version: AMD Opteron
Voltage: 1.2 V
External Clock: 200 MHz
Max Speed: 2100 MHz
Current Speed: 2100 MHz
Status: Populated, Enabled
Upgrade: <OUT OF SPEC>
L1 Cache Handle: 0x000C
L2 Cache Handle: 0x000D
L3 Cache Handle: 0x000E
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified

You probably have processor frequency scaling enabled, that is to say, when the load is low, each of the core clock speeds slow down. To test, just do 4 intensive processes (such as cat /dev/urandom > /dev/null &) , and then re-run cat /proc/cpuinfo | grep -E "processor|MHz" (just to simplify the output a little):You should see one of the processor's cores now registering the full 2.1GHz.

Interesting /cat/proc/cpuinfo see's 4 Hyperthreaded Cores (so it ;ists 8 CPU's)... while DMI decode does not recognize the CPU family and only shows two cores ..

dmidecode see's the CPU frequency properly , while /proc/cpuinfo see's it as 1.3 Ghz..



for grins could I see the output of lspci I'd like to see if RHEL 5 recognizes your Motherboard Chipset properly among other things..


Is this RHEL 5.2 by chance ? just want to know if you are running the latest update or not.

processor : 0
cpu MHz : 1300.000
processor : 1
cpu MHz : 1300.000
processor : 2
cpu MHz : 2100.000
processor : 3
cpu MHz : 1300.000
processor : 4
cpu MHz : 1300.000
processor : 5
cpu MHz : 1300.000
processor : 6
cpu MHz : 1300.000
processor : 7
cpu MHz : 1300.000


You are so right. Does that mean there is a "frequency scaling" setting in BIOS? And I should disable it.

There's no reason I am aware of for disabling it; the speed of each core increases when the load demands it. As a bonus, it uses less power, which is why this frequency scaling is common in laptops. I'm sure you can disable by removing the appropriate module from the kernel. Not sure which one that is though.