I was trying to compile ATLAS (Automatically Tuned Linear Algebra Software) to install Kaldi on my new archlinux computer, and I ran into this error :
CPU Throttling apparently enabled! It appears you have cpu throttling enabled, which makes timings unreliable and an ATLAS install nonsensical. Aborting. See ATLAS/INSTALL.txt for further information xconfig exited with 1
Of course, the first thing I did was to check Google for the error, and the answer was pretty clear: disable CPU Throttling. "Cool story bro", but how can I do it?
I had to set the scaling governor of my cpus to performance. So did I.
First by modifying directly the files with this command line (using bash):
for CPUFREQ in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do [ -f $CPUFREQ ] || continue; echo -n performance > $CPUFREQ; done
Of course, it didn't work.
Then, as mentionned on the Archlinux wiki page I used
cpupower frequency-set -g performance
Of course again, it didn't work.
Then I found the Holy Grail with this post on StackExchange. The problem is specific to the intel_pstate governor (default for Intel Sandy Bridge and Ivy Bridge CPUs as of kernel 3.9). So the solution is simply to disable it and load the
acpi-cpufreq module. And Ta-da!