Disable CPU throttling temporarily

WoxDN · 08-26-2015, 09:48 AM

I tried several things to turn off CPU throttling an a Debian 2.6 machine (I need it temporarily to install ATLAS):

Code:

for CPUFREQ in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do
    [ -f $CPUFREQ ] || continue;
    echo -n ondemand > $CPUFREQ;
done
/usr/bin/cpufreq-selector -g performance
/etc/init.d/cpufrequtils restart

But none of it worked:

Code:

grep -E '^model name|^cpu MHz' /proc/cpuinfo

model name	: Intel(R) Xeon(R) CPU E5-2650 0 @ 2.00GHz
cpu MHz		: 1200.000
model name	: Intel(R) Xeon(R) CPU E5-2650 0 @ 2.00GHz
cpu MHz		: 1200.000
model name	: Intel(R) Xeon(R) CPU E5-2650 0 @ 2.00GHz
cpu MHz		: 1200.000
model name	: Intel(R) Xeon(R) CPU E5-2650 0 @ 2.00GHz
cpu MHz		: 1200.000

I also find posts which mention disabling ondemand or kondemand with update-rc, but it can't find any ondemand or kondemand init scripts. Any suggestions on how to disable kondemand (I have kondemand/0, kondemand/1, etc. running)? Or other solutions to temporarily disable throttling?

smallpond · 08-26-2015, 04:34 PM

List available governors

Code:

cpufreq-info -g
ondemand userspace performance

Disable throttling

Code:

for CPUFREQ in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor;
  do
    [ -f $CPUFREQ ] || continue
    echo -n performance > $CPUFREQ
  done

WoxDN · 08-27-2015, 03:58 AM

Yes, sorry, that was what I tried but didn't work (performance instead of ondemand in original post).

rtmistler · 08-27-2015, 07:26 AM

I can't find the code where I did this before, however I recall that I explored the governors too and that didn't work. What did work was setting the CPU speed exactly to what I wanted it to be and also setting the max and min values to the same single desired frequency.

TobiSGD · 08-27-2015, 07:32 AM

Why not just go to your BIOS/UEFI and disable frequency scaling (throttling is a totally different thing)?

WoxDN · 08-27-2015, 12:09 PM

For the BIOS option I need to reboot the PC and I cannot do that. As for forcing CPU speeds, do you remember where this can be done? The file "scaling_setspeed" contains "<unsupported>" and the other frequency related files have read-only permissions by default (which probably means I shouldn't change them).

ondoho · 08-27-2015, 02:11 PM

i once tried this, long time ago, and iirc the "userspace" governor was playing a key role.

maybe it went sth like this:
setting the "userspace" governor allows the user to change between ondemand/performance?

TobiSGD · 08-28-2015, 03:37 AM

Quote:

Originally Posted by ondoho

i once tried this, long time ago, and iirc the "userspace" governor was playing a key role.

maybe it went sth like this:
setting the "userspace" governor allows the user to change between ondemand/performance?

The userspace governor is used when you use additional programs that set the frequency, it is not needed to choose between other governors.