Re: [BUG] wrong bogomips values with kernel 2.6.16

[Knut Petersen <Knut_Petersen@t-online.de>]

Linus Torvalds wrote:

> On Wed, 22 Mar 2006, Knut Petersen wrote:
>  
>
> > All Pentium M, Xeon up to model 2 and the P6 family increment with every
> > internal processor cycle.
> >    
>
> Just to humor me. Try the bogomips loop in user space with something like 
> the appended (make sure the frequency is fixed to the lowest frequency).
>
> 		Linus
>  
No problem ...

linux:~ # cat 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
1867000 1600000 1333000 1067000 800000

linux:~ # echo 800000 > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed;cat 
/proc/cpuinfo;./test
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 13
model name      : Intel(R) Pentium(R) M processor 1.86GHz
stepping        : 8
cpu MHz         : 800.000
cache size      : 2048 KB
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 clflush dts acpi mmx fxsr sse sse2 ss tmpbe nx est tm2
bogomips        : 3730.27

TSC: 798.307872 MHz




linux:~ # echo 1067000 > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed;cat 
/proc/cpuinfo;./test
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 13
model name      : Intel(R) Pentium(R) M processor 1.86GHz
stepping        : 8
cpu MHz         : 1067.000
cache size      : 2048 KB
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 clflush dts acpi mmx fxsr sse sse2 ss tmpbe nx est tm2
bogomips        : 4975.25

TSC: 1064.407897 MHz



linux:~ # echo 1333000 > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed;cat 
/proc/cpuinfo;./test
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 13
model name      : Intel(R) Pentium(R) M processor 1.86GHz
stepping        : 8
cpu MHz         : 1333.000
cache size      : 2048 KB
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 clflush dts acpi mmx fxsr sse sse2 ss tmpbe nx est tm2
bogomips        : 6215.57

TSC: 1330.511688 MHz


linux:~ # echo 1600000 > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed;cat 
/proc/cpuinfo;./test
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 13
model name      : Intel(R) Pentium(R) M processor 1.86GHz
stepping        : 8
cpu MHz         : 1600.000
cache size      : 2048 KB
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 clflush dts acpi mmx fxsr sse sse2 ss tmpbe nx est tm2
bogomips        : 7460.55

TSC: 1596.612533 MHz


linux:~ # echo 1867000 > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed;cat 
/proc/cpuinfo;./test
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 13
model name      : Intel(R) Pentium(R) M processor 1.86GHz
stepping        : 8
cpu MHz         : 1867.000
cache size      : 2048 KB
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 clflush dts acpi mmx fxsr sse sse2 ss tmpbe nx est tm2
bogomips        : 8705.53

TSC: 1862.715048 MHz


I tried kernel _2.6.15_ too - it´s even more broken:

linux:~ # cat /proc/cpuinfo;./test
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 13
model name      : Intel(R) Pentium(R) M processor 1.86GHz
stepping        : 8
cpu MHz         : 4347.853
cache size      : 2048 KB
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 clflush dts acpi mmx fxsr sse sse2 ss tmpbe nx est tm2
bogomips        : 8702.35

TSC: 1863.086854 MHz

Isn´t that nice? I´m able to overclock my 1.86 MHz cpu to stable 4.35 MHz
with just a passive heatsink ;-)))

cu,
Knut
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