1. Download cpudyn latest version (0.99.0, 13-Feb-2004) from the official site and decompress the file (my ~/tmp/ directory is used in this page examples, change "benjami" to your user name):
   
   benjami@codol:~> cd tmp
   benjami@codol:~/tmp> wget http://mnm.uib.es/~gallir/cpudyn/download/cpudyn-0.99.0.tgz
   benjami@codol:~/tmp> tar zxvf cpudyn-0.99.0.tgz
   
   
2. Change to root user, go to the new cpudyn folder, compile and install:
   
   benjami@codol:~/tmp> su -
   Password:
   codol:~ # cd /home/benjami/tmp/cpudyn/
   (this is a copy&paste: of course, you should change the "benjami" with your user name) codol:/home/benjami/tmp/cpudyn # make install
   
   
   
3. Now you can manually start cpudyn daemon:
   
   codol:/home/benjami/tmp/cpudyn # /etc/init.d/cpudyn start
   
   
4. But cpudyn daemon needs the appropiate processor Kernel module working.  One simptom that you don't have the module is that /proc/cpufreq file is empty:
   
   codol:/home/benjami/tmp/cpudyn # cat /proc/cpufreq
             minimum CPU frequency  -  maximum CPU frequency  -  policy
   codol:/home/benjami/tmp/cpudyn #
   
   
5. P4-clockmod is the appropiate module for the Pentium 4 M processor.  Probe it:
   
   codol:/home/benjami/tmp/cpudyn # modprobe p4-clockmod
   
   If you no receive any error, the module is working and you can see it with lsmod:
   
   codol:/home/benjami/tmp/cpudyn # lsmod | grep p4-clockmod
   p4-clockmod             1488   0  (unused)
   freq_table              1376   0  [p4-clockmod]
   
   
6. Now you can see changes in the /proc/cpufreq file:
   
   codol:/home/benjami/tmp/cpudyn # exit
   logout
   benjami@codol:~/tmp> cat /proc/cpufreq
             minimum CPU frequency  -  maximum CPU frequency  -  policy
   CPU  0       149519 kHz ( 12 %)  -    1196153 kHz (100 %)  -  performance
   
   ... when the chip is in perfomance mode, and when is powersaving ...
   
   benjami@codol:~/tmp> cat /proc/cpufreq
             minimum CPU frequency  -  maximum CPU frequency  -  policy
   CPU  0       149519 kHz ( 12 %)  -    1196153 kHz (100 %)  -  powersave
   
   watch is great to constantly see this file contents:
   
   benjami@codol:~/tmp> watch -n 1 cat /proc/cpufreq
   
   
7. Finally, you can use YaST2 in order to load the p4-clockmod module and cpudyn daemon at startup. YasT2 allows to change the cpudyn parameters too:
   
   
1. Figure 1: Load p4-clockmod module on startup.
   Go to YaST2 Control Center > System > Editor for /etc/sysconfig Files.  Now select System > Kernel > MODULES_LOADED_ON_BOOT in the left tree.  Add p4-clockmod to the existing list.
   
   
2. Figure 2: Start cpudyn daemon on startup.
   Go to YaST2 Control Center > System > Runlevel Editor.  Click Runlevel properties button. Search cpudyn in the list.  Select 3 i 5 in the Service will be started in following runlevels section, and clic the Finish button.
   
   
3. Figure 3: Change cpudyn parameters.
   Go to YaST2 Control Center > System > Editor for /etc/sysconfig Files.  Now select Other > etc > sysconfig > cpudyn > OPTS in the left tree.  To see all of the parameter possibilities, run man cpudynd or read the official homepage examples and FAQ section.
   

Other modules

• Centrino: speedstep_ICH or speedstep_smi («I'm not sure», says the post author)
• Pentium III: freq_table and speedstep
• AMD: powernow-k6, powernow-k7 and powermate
• AMD Athlon Mobile: powernow-k7