odroid-xu4:application_note:software:cpufrequtils_cpufreq_govornor [ODROID Wiki]

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====== Cpufrequtils ======

Dynamic CPU frequency scaling (also known as CPU throttling) is a technique in computer architecture where a processor is run at a less-than-maximum frequency in order to conserve power.


Here is a setup process using "cpufrequtils".

=== 1. Install "cpufrequtils" ===

<code bash target>
$ sudo apt-get install cpufrequtils
</code>

=== 2. Set governor and cpu speed  ===
You need to create **/etc/default/cpufrequtils** file and fill it as the following format.
<code bash target>
$ sudo vi /etc/default/cpufrequtils
</code>
<code bash target>
ENABLE="true"
GOVERNOR="ondemand"
MAX_SPEED=1536000
MIN_SPEED=100000
</code>
You can check the available list of governor and cpu speed under those nodes.
<code>
/sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors
</code>
<code>
/sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies
</code>

=== 3. Restart cpufrequtils service ===
Restart cpufrequtils service.
<code bash target>
$ sudo service cpufrequtils restart
</code>
Then, you can check the cpufreq info is updated.
<code bash target>
$ cpufreq-info -o
          minimum CPU frequency  -  maximum CPU frequency  -  governor
CPU  0       100000 kHz (  6 %)  -    1536000 kHz (100 %)  -  ondemand
CPU  1       100000 kHz (  6 %)  -    1536000 kHz (100 %)  -  ondemand
CPU  2       100000 kHz (  6 %)  -    1536000 kHz (100 %)  -  ondemand
CPU  3       100000 kHz (  6 %)  -    1536000 kHz (100 %)  -  ondemand
</code>

=== 4. [Option] Ubuntu 18.04 - Disable ondemand.service using systemctl ===
In case of <color #ed1c24>**Ubuntu 18.04**</color>, ondemand.service overrides the default governor, so you should disable it to use cpufrequtils.
<code bash target>
$ sudo systemctl disable ondemand
</code>

If you want to restore this service as default, please use this command.
<code bash target>
$ sudo systemctl enable ondemand
</code>


===== Set-up Examples =====
=== [Example] ODROID-N2 ===
== Available governor and cpu frequency sets ==
<code bash target>
$ cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors 
ondemand powersave userspace conservative interactive performance schedutil 
</code>
<code bash target>
$ cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies 
100000 250000 500000 667000 1000000 1200000 1398000 1512000 1608000 1704000 1896000

$ cat /sys/devices/system/cpu/cpufreq/policy2/scaling_available_frequencies                                                          
100000 250000 500000 667000 1000000 1200000 1398000 1512000 1608000 1704000 1800000 
</code>

== cpufrequtils option ==
<code bash target>
$ sudo vi /etc/default/cpufrequtils

ENABLE="true"
GOVERNOR="ondemand"
</code>

== cpufreq-info ==
<code bash target>
$ sudo service cpufrequtils restart

$ cpufreq-info -o
          minimum CPU frequency  -  maximum CPU frequency  -  governor
CPU  0       100000 kHz (  5 %)  -    1896000 kHz (100 %)  -  ondemand
CPU  1       100000 kHz (  5 %)  -    1896000 kHz (100 %)  -  ondemand
CPU  2       100000 kHz (  5 %)  -    1800000 kHz (100 %)  -  ondemand
CPU  3       100000 kHz (  5 %)  -    1800000 kHz (100 %)  -  ondemand
CPU  4       100000 kHz (  5 %)  -    1800000 kHz (100 %)  -  ondemand
CPU  5       100000 kHz (  5 %)  -    1800000 kHz (100 %)  -  ondemand
</code>
=== [Example] ODROID-XU3/XU4 ===
== Available governor and cpu frequency sets ==
<code bash target>
$ cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors
conservative userspace powersave ondemand performance schedutil
</code>
<code bash target>
$ cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies
200000 300000 400000 500000 600000 700000 800000 900000 1000000 1100000 1200000 1300000 1400000 1500000
$ cat /sys/devices/system/cpu/cpufreq/policy4/scaling_available_frequencies
200000 300000 400000 500000 600000 700000 800000 900000 1000000 1100000 1200000 1300000 1400000 1500000 1600000 1700000 1800000 1900000 2000000
</code>

== cpufrequtils option ==
<code bash target>
$ sudo vi /etc/default/cpufrequtils

ENABLE="true"
GOVERNOR="ondemand"
</code>

== cpufreq-info ==
<code bash target>
$ sudo service cpufrequtils restart

$ cpufreq-info -o
          minimum CPU frequency  -  maximum CPU frequency  -  governor
CPU  0       200000 kHz ( 13 %)  -    1500000 kHz (100 %)  -  ondemand
CPU  1       200000 kHz ( 13 %)  -    1500000 kHz (100 %)  -  ondemand
CPU  2       200000 kHz ( 13 %)  -    1500000 kHz (100 %)  -  ondemand
CPU  3       200000 kHz ( 13 %)  -    1500000 kHz (100 %)  -  ondemand
CPU  4       200000 kHz ( 10 %)  -    2000000 kHz (100 %)  -  ondemand
CPU  5       200000 kHz ( 10 %)  -    2000000 kHz (100 %)  -  ondemand
CPU  6       200000 kHz ( 10 %)  -    2000000 kHz (100 %)  -  ondemand
CPU  7       200000 kHz ( 10 %)  -    2000000 kHz (100 %)  -  ondemand
</code>
=== [Example] ODROID-C2 ===
== Available governor and cpu frequency sets ==
<code bash target>
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
hotplug interactive conservative ondemand userspace powersave performance
</code>
<code bash target>
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
100000 250000 500000 1000000 1296000 1536000
</code>

== cpufrequtils option ==
<code bash target>
$ sudo vi /etc/default/cpufrequtils

ENABLE="true"
GOVERNOR="performance"
MAX_SPEED=1536000
MIN_SPEED=100000
</code>

== cpufreq-info ==
<code bash target>
$ sudo service cpufrequtils restart

$ cpufreq-info -o
          minimum CPU frequency  -  maximum CPU frequency  -  governor
CPU  0       100000 kHz (  6 %)  -    1536000 kHz (100 %)  -  performance
CPU  1       100000 kHz (  6 %)  -    1536000 kHz (100 %)  -  performance
CPU  2       100000 kHz (  6 %)  -    1536000 kHz (100 %)  -  performance
CPU  3       100000 kHz (  6 %)  -    1536000 kHz (100 %)  -  performance
</code>

=== [Example] ODROID-C1 ===

== Available governor and cpu frequency sets ==
<code bash target>
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
hotplug interactive conservative ondemand performance
</code>
<code bash target>
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
96000 192000 312000 408000 504000 600000 696000 816000 912000 1008000 1104000 1200000 1296000 1416000 1488000 1536000 1632000 1728000 1824000
</code>

== cpufrequtils option ==
<code bash target>
$ sudo vi /etc/default/cpufrequtils

ENABLE="true"
GOVERNOR="ondemand"
MAX_SPEED=1824000
MIN_SPEED=100000
</code>
== cpufreq-info ==
<code bash target>
$ sudo service cpufrequtils restart

$ cpufreq-info -o
          minimum CPU frequency  -  maximum CPU frequency  -  governor
CPU  0        96000 kHz (  5 %)  -    1824000 kHz (100 %)  -  ondemand
CPU  1        96000 kHz (  5 %)  -    1824000 kHz (100 %)  -  ondemand
CPU  2        96000 kHz (  5 %)  -    1824000 kHz (100 %)  -  ondemand
CPU  3        96000 kHz (  5 %)  -    1824000 kHz (100 %)  -  ondemand
</code>