====== Ubuntu - CPU - Create 100% CPU Load ======

To stress test and benchmark certain key aspects of it including CPU performance. 

----

===== Install Stress or Stress-ng =====

<code bash>
sudo apt install stress 
</code>

or

<code bash>
sudo apt install stress-ng
</code>

<WRAP info>
**NOTE:**  **stress-ng** is a newer version of stress that ships in with extra features.
</WRAP>


----

===== Impose 100% CPU Load =====

Run **stress** or **stress-ng**.

<code bash>
sudo stress-ng --cpu 4 -v --timeout 30s
</code>

<WRAP info>
**NOTE:**  where 

  * **--cpu**:  Specifies the number of cores.
  * **-v**:  Enables verbose mode.
  * **--timeout**:  Specifies the time after which the command will terminate.

</WRAP>

----

===== Check CPU usage =====

<code bash>
top
</code>

----

===== Other methods to create 100% CPU load =====

<code bash>
yes > /dev/null &
</code>

**NOTE:**  This only imposes 100% load on a single core.

To impose this against multiple cores, then run the command multiple times to exhaust all the CPU power:

<code bash>
yes > /dev/null &
yes > /dev/null &
yes > /dev/null &
yes > /dev/null &
</code>

<WRAP info>
**NOTE:**  To terminate the Linux background jobs created by the above commands:

<code bash>
killall yes
</code>

</WRAP>

----

===== Another method to produce 100% CPU load usage =====

<code bash>
dd if=/dev/zero of=/dev/null
</code>

To fully utilize all the cores on your system, run the following command:

<code bash>
fulload() { dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null & }; fulload; read; killall dd
</code>

<WRAP info>
**NOTE:**  The number of the above command in the function should be equal to the number of cores (for example 4 in this case).
</WRAP>

----