High CPU usage applet

Jan Claeys lists at janc.be
Tue May 12 00:48:35 UTC 2009

Op vrijdag 08-05-2009 om 00:40 uur [tijdzone -0400], schreef Timo
> Somewhat relevant, yes, but I think people talking in that page don't  
> understand correctly the root cause of the problem. Linux scheduler is  
> good enough nowadays that even lots of processes all eating 100% CPU  
> don't make the system unusable. The problem comes from when some  
> process eats all the memory and starts forcing other processes to swap.

That's not the only reason why your system might get sluggish.

> I just tested this actually. I created 100 processes running an  
> infinite loop, causing the system load on a 2 core machine to hit 100.  
> It was a bit sluggish, but still perfectly usable.

Try adding one of the following in a (tight) infinite loops:
      * some disk (or similar) I/O, syncing very often (doing lots of
        small database inserts & commits might be a good example)
      * an expensive syscall, preferably one that locks out the other
        processes wanting to access the same kernel/system resource

Now try again...  ;)

Jan Claeys

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