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Re: CPU usage mysteriously spiking after kernel upgrade



On Tue, May 03, 2011 at 07:39:37PM -0700, John Magolske wrote:
> After updating the kernel on my ThinkPad from linux-image-2.6.28-grml
> to linux-image-2.6.31-grml I've noticed cpu usage periodically jumping
> from 600MHz to 1500MHz several times a minute. This is with not much
> going on but Vim, Mutt & ELinks running in a screen session in a
> framebuffer console. Top shows nothing under the %CPU column...I don't
> see anything pass much beyond 1%.
> 
> Any thoughts as to what could be causing this and/or suggested
> techniques for determining the culprit would be much appreciated.

Has your CPU governor changed, perhaps, to something more 'twitchy'?
Try:
   cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

If this returns "ondemand", for example, the CPU will jump to a higher
frequency more readily than, say "conservative". To change it,
temporarily, echo one of the words in
/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors to
/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor and see whether
that helps.

> 
> Regards,
> 
> John
> 
> -- 
> John Magolske
> http://B79.net/contact
> 
> 
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