Turning off CPU throttling

Mandatory !

Manually

You need to write "performance" in the file /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

This should be done for each core available (replace "cpu0" with "cpu1" "cpu2" etc... in the path)

With cpufrequtils

Install the package

sudo apt-get install cpufrequtils

Set cpu 0 to performance mode :

sudo cpufreq-set --cpu 0 -g performance

This should also be done for each core available with the --cpu parameter

Dependencies

ATLAS needs a fortran compiler

sudo apt-get install libgfortran3

Download

The ATLAS source can be found at ​http://sourceforge.net/projects/math-atlas/files/

Untar the file anywhere ( ~/ATLAS for instance )

Installation

Create a build directory (~/ATLAS_build for instance) and enter it (cd ~/ATLAS_build).

Launch "configure" from the atlas source directory

~/ATLAS/configure

Option "-t" speicifies the number of threads that will be used by the library after compilation.

"-t -1" for autodetect

"-t 0" for unthreaded

"-t x" for x threads

Then run

make
make check
make ptcheck
make time
make install