CPU Frequency Scaling

**Javasnob** · 06-13-2006

I recently reinstalled Gentoo Linux on my main machine, and I've had no problems thus far, only my CPU frequency scaling seems a bit off. cpufreq-info used to say that the available frequencies were from 300MHz to 2.4GHz in increments of 300 MHz, but now it reports that my hardware limits are 2.1 and 2.4GHz. Does anyone have an idea on how I can fix this?

Thanks!

**antidrugue** · 06-14-2006

Which exact CPU do you have?

Code:

cat /proc/cpuinfo

Which cpufreq policy are you using?

Code:

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

And what says

Code:

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq

And finally which modules take care of the stepping?

Code:

cpufreq-info | grep driver

Do you have anything regarding cpu power management enabled in the BIOS?

**Javasnob** · 06-14-2006

Here's the output from the suggested commands:

Code:

rob@TheRing ~ $ cat /proc/cpuinfo | grep "model name"
model name      : Intel(R) Pentium(R) 4 CPU 2.40GHz
model name      : Intel(R) Pentium(R) 4 CPU 2.40GHz
rob@TheRing ~ $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor 
ondemand
rob@TheRing ~ $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq 
2100000
rob@TheRing ~ $ cpufreq-info | grep driver
  driver: p4-clockmod
  driver: p4-clockmod

The unusual thing is as I said: before, the minimum frequency was 300MHz; now it's 2.1GHz.

I'll check out my BIOS to see if there's an option, but I haven't touched it since my reinstall, so I don't think that's it.

Thanks for the help!

**antidrugue** · 06-14-2006

And what about the avalaible frequencies?

Code:

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

You can force the minimal value you get out of this in scaling_min_freq.

Also make sure the minimal frequency is not being set at boot in /etc/sysfs.conf.

**Javasnob** · 06-14-2006

Code:

rob@TheRing ~ $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies 
2100000 2400000

Also, I don't have a /etc/sysfs.conf. =(

**antidrugue** · 06-14-2006

Well that's certainly interesting.

So you did compile the kernel yourself?
Which one is it?

I know you have CPU frequency enabled in the kernel and Pentium 4 clock modulation, but do you have Processor ACPI support enabled?

Originally Posted by Make menuconfig

Power management options (ACPI, APM) --->
ACPI (Advanced Configuration and Power Interface) Support --->
<M> Processor

It isn't required by "p4-clockmod", but I guess it must be useful to decode the proper CPU frequency tables.

**Javasnob** · 06-14-2006

My kernel is self-compiled, and it's version 2.6.16.

And I do have ACPI Processor support built into my kernel.

**antidrugue** · 06-14-2006

Did you compile it with the kernel config as you had before?

And what about :

Code:

cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq

Are you using any kind of daemon for CPU management (powersaved, cpudyn,cpufreq, etc.) ?

**Javasnob** · 06-14-2006

Yes, I simply copying my .config file over.

Code:

rob@TheRing ~ $ cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq
2100000

And no, I'm not using a daemon for CPU management.

**antidrugue** · 06-14-2006

So it's the same exact kernel version?

And what about

Code:

dmesg | grep -i cpu

And

Code:

cat /var/log/messages | grep -i cpu

?

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