CPU throttling problems

Eduardo Robles Elvira edulix at gmail.com
Tue Apr 12 22:31:15 UTC 2005

hi people !

I'm having big headhaches with my laptop and (k)ubuntu. It happens that every 
once in a while, system heats and thus laptop fan start to spin. And that's 
when my system becomes _slow_.

I've found that normally my system has CPU Throttling to 0%, but when it 
becomes slow it turns to 75%. And I've also found that you can see actual 
throttling state by executing:

$ sudo cat /proc/acpi/processor/CPU0/throttling

and you can modify it by doing:

$ sudo echo <number from 0 [0%] to 8 [85%]> 
> /proc/acpi/processor/CPU0/throttling

But it happens that when fan start spinning and throttling turns to 7,  "$ 
sudo echo 0 > /proc/acpi/processor/CPU0/throttling" stop working. It just 
doesn't obey me! Obviously, when I change throttling via klaptop system tray 
icon, it doesn't obey me neither.

How could I fix this situation? I don't want throttling to change from 0. I 
want it _always_ in 0! I've tried to tue my system configuration with klaptop 
but that doesn't work, belive me...

Ah also, I wouldn't blame to BIOS or something like that: I have been using 
suse for nearly 6 months in this laptop, and this problems _never_ happened 
to me. I still have it installed and it just doesn't have this problem.

Can anyone help me please ? My temporal solution is just disabling throttling 
in the kernel. Via lsmod I've seen that I have loaded a module called 
"acpi_cpufreq", so I thought that maybe if I disable it I could just stop all 
the whole problem.

That module doesn't appear in /etc/modules so I thought that most probably  
it's bbeing loaded by hotplug. It doesn't appear to be the case neither, 
because I've added acpi_cpufreq to /etc/hotplug/blacklist, but it's still 
lodaded at boot!

Can anyone show me a light, even if it's damn small ? I just need one ;-).

Thanks for your time,

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