686 kernel wastes CPU power

Matt Patterson matt at v8zman.com
Thu Apr 13 18:09:09 UTC 2006

I am not terribly concerned about verifying that more processor time is
being used. The fan runs more, the temp is hotter, and the battery life is
shorter. Using the basic tools like top, I see things like "system monitor",
xorg, firefox, gnome-terminal all taking much larger chunks of cpu when I
run the 686 kernel.

I am not familiar with how to test an applications performance/cpu usage
using time. If someone offers a quick tutorial I will be happy to do the
tests and report here.

One clue that I think may be related is that I have noticed a different feel
under the 386 kernel. The responsiveness, entirely unrelated to the machine
speed (which is always adequate), is slower in the 386 kernel. Mouse clicks
react less quickly, etc. Perhaps the 686 kernel enables more aggressive
polling of certain functionalities and thus impacts more on the CPU.


On 4/13/06, Dick Davies <rasputnik at gmail.com> wrote:
> On 12/04/06, Matt Patterson <matt at v8zman.com> wrote:
> > I just ran a dapper update a few days ago, and at the same time I
> switched
> > to the 686 kernel (had been running 386 kernel). After the update I
> noticed
> > a huge hit to my CPU usage (sucking down my battery life). Just sitting
> in
> > gnome with a terminal running top could take 11% and running the system
> > monitor would take 40%. I went back to the 386 kernel (the newest dapper
> > one) and those numbers dropped to 0.1% and 5% respectively.
> >
> > Anybody have any clues?
> Bear in mind that top, etc. pull their stats out of proc.
> They can only report the statistics provided by the kernel.
> --
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> http://number9.hellooperator.net/
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