Re: Slower CPU frequency reported by the kernel

[Paolo Ornati <ornati@fastwebnet.it>]

On Fri, 2 Feb 2007 12:11:25 +0100
"Francis Moreau" <francis.moro@gmail.com> wrote:

> Hi,
> 
> I'm using a PC with AMD 64 3000+ cpu which is theoricaly running at
> 2Ghz. But when looking at /proc/cpuinfo, the kernel reports that it
> runs only at 1Ghz:
> 
> # cat /proc/cpuinfo
> 
> processor       : 0
> vendor_id       : AuthenticAMD
> cpu family      : 15
> model           : 12
> model name      : AMD Athlon(tm) 64 Processor 3000+
> stepping        : 0
> cpu MHz         : 1000.000
> cache size      : 512 KB
> fdiv_bug        : no
> hlt_bug         : no
> f00f_bug        : no
> coma_bug        : no
> fpu             : yes
> fpu_exception   : yes
> cpuid level     : 1
> 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 syscall nx mmxext lm
> 3dnowext 3dnow ts fid vid ttp
> bogomips        : 2004.89
> 
> I tried with a 2.6.20-rc7 kernel and still have the same.
> 
> What's going wrong ?


You are using frequency scaling(*) and "/proc/cpuinfo" reflects the
current speed.


(*) = 
#
# CPU Frequency scaling
#
CONFIG_CPU_FREQ=y
CONFIG_CPU_FREQ_TABLE=y
CONFIG_CPU_FREQ_DEBUG=y
CONFIG_CPU_FREQ_STAT=m
CONFIG_CPU_FREQ_STAT_DETAILS=y
# CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set
CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y
CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
CONFIG_CPU_FREQ_GOV_POWERSAVE=m
CONFIG_CPU_FREQ_GOV_USERSPACE=y
CONFIG_CPU_FREQ_GOV_ONDEMAND=m
CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m


Read "Documentation/cpu-freq/user-guide.txt" for more info.

-- 
	Paolo Ornati
	Linux 2.6.20-rc7 on x86_64