[SGVLUG] CPU speed scaling

[Mike Fedyk]

Dustin wrote:

>On Wed, 23 Nov 2005, Mike Fedyk wrote:
>
>  
>
>>I used a p4 laptop with speedstep (two speed: 1.6 or 2.8ghz) for a while 
>>with FC4 and didn't notice anything showing in the cpu monitor.  Nice 
>>thing is that it would step up to the fast speed when needed, but would 
>>drain the battery in 15 minutes going at full speed.  Otherwise I'd get 
>>~2 hours on the battery.
>>    
>>
>
>I seem to have solved this problem mostly.  I have started tossing out
>unnecessary crap out of the kernel, and on the first pass I tossed out
>ACPI extras for IBM and Toshiba laptops, and suddenly the CPU activity
>went from somewhat insane to barely noticable on the graph and no
>noticable response degradation, and scaling also started working a lot
>better.  I suspect it was loading the wrong laptop driver.
>
>Heh.  Sometimes it still pays to build your own kernel.
>  
>
Don't let this go unreported to a BTS.  At the very least someone will 
be able to find it there if they run into the problem.

If you can, do a binary search on the options you removed to find the 
config option that triggered the problem.

Mike