I'm running Fedora Core 1 with the basic FC1 kernel (2.4.22-1.2174.nptl). My computer has a P4-M so it uses Speedstep (in Windows). I was reading up on throttling in Linux and from what I found you can either use ACPI (which isn't built into this kernel) or cpufreq. I have a cpufreq file in /proc but its contents are as follows:

minimum CPU frequency - maximum CPU frequency - policy

That's it... there's no values or anything. I tried using cpudyn but it didn't work because that file didn't have the right information or something. I'm not supposed to manually edit this file, am I? Anybody have any suggestions?

Thanks,
Mike

Actually ACPI is built into the kernel:
become root
cd /boot/grub/grub.conf
then edit this line: kernel /vmlinuz-2.4.22-1.2174.nptl ro root=LABEL=/ hdc=ide-scsi acpi=on
now when you reboot acpi will be enabled.

Then to throttle the cpu you would have to go to /proc/acpi/processor/CPU0
Then issue the command cat throttling see what it says.

You can change the throttling by eg: echo 2 > throttling and this will throttle your cpu.

You might also want to have a read here: http://www.linux.org/docs/ldp/howto/...usingacpi.html

HTH

cool, thanks. so i enabled acpi and now i have all these things in /proci/acpi... so now you were saying i could enable throttling by running "echo 2 > throttling" but i havent done that just yet... in /proc/acpi/processor/CPU0 i have a file called performance and it says theres 2 performance states, P0 and P1... P0 being 1700 MHz and P1 being 1200 MHz... i don't anything about echo so how would i go about using that to change from P0 to P1?

Thanks,
Mike

I'm not familiar with the performance since my laptop doesn't inculde it but you would use the same command as throttling

echo 1 > performance

That should do it, I did finally remember the site I came by before take a look here:

http://acpi.sourceforge.net/documentation/index.html

Enjoy !

Try this link, I hope it will help you:

http://bulma.net/body.phtml?nIdNoticia=1946

Fred.

Thanks for all the help. I went to some of those sites and messed around with a few things, but for the most part I found out KLaptop can be used to change the processor frequency so I'm just using that. But I have been having fun turning on the fans manually... :-P

Mike

Ok, well I don't know what I did, but now I can't get my computer to run at full speed when on battery. It's grayed out in KLaptop and when i do "echo 0 > performance" in /proc/acpi/processors/CPU0 it doesn't do anything. Any ideas?

Mike

Did you try plugging the laptop back in? If so then were you able to get 100%, if so your bios may automatically throttle the laptop back when running on battery.

This thing is all screwy. I shut it down (unplugged) to go to class and turned it back on (unplugged) when I got home. Now it's allowing me to change between 1.7 and 1.2 GHz... weird.

Mike