suspend on 'idle'

Richard A. Smith richard at
Thu Aug 7 12:52:44 EDT 2008

Mikus Grinbergs wrote:

> would like 'idle' to mean "processor is idle" -- not just "keyboard 
> is idle" (of course my keyboard is idle -- I'm waiting for the 
> still-ongoing downloads to finish before I type the next command).

Good idle detection is hard.  What you are really wanting is "system 
idle" which requires a holistic approach rather than just a few subsystems.

For example any device that is doing a large ammount of bus mastered DMA 
transactions will have a fairly low CPU usage but the system is 
certainly not idle.  There are many workloads where our current 
heuristics fail.

We hope to use the cpuidle subsystem + hints from apps to manage this 
but theres still a lot of work do me done here.

Richard Smith  <richard at>
One Laptop Per Child

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