[sf-lug] what is kondemand and how to put it in a cage?

Rick Moen rick at linuxmafia.com
Fri Aug 17 12:51:55 PDT 2012

Quoting Jim Stockford (jim at systemateka.com):

>     Anybody know what is kondemand? 

Looks like a Linux kernel thread (which is why it shows in square
brackets in top or ps) that is the kernel interface for CPU frequency
scaling, and is part of the power-management subsystem.  (The 'k' is for
kernel, not KDE.)  It is classed as a 'governor' for frequency-scaling
purposes, and changes the CPUs' p-state (power-management state) and CPU
frequency depending on system demand.[1]  You will find that there is
one kondemand thread per CPU core. 

It's basically part of the kernel background services.  I wouldn't worry
about it -- unless you want to rev up CPU speed a bit for performance
purposes, in which case please see referenced kernel doc in my footnote.

> My machine has slowed waaaay down.

You might be able to tune power-management to give you less CPU
relaxation and more horsepower.

[1] See section 2.4 in
https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt .  
Where this document talks about a CPUfreq governor called 'ondemand',
that's the same thing as kondemand, as the k is a prefix convention
meaning kernel thread.

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