[ltp] Frustrating powertop results for a22m

[Tino Keitel]

On Thu, Feb 14, 2008 at 15:09:08 -0500, Connor Behan wrote:
> If I run Powertop when X is running, about 50% of my wakeups say "extra  
> timer interrupt" and if X is not running, about 80% of them say that.  
> All of the suggestions online of how to fix this say to enable CPU  
> frequency scaling and to set HPET as the timer.

How many are 80%?

What kernel do you use?

With 2.6.23 and before, you should use the hrtimers patches by Thomas
Gleixner (google for hrtimers tglx). With 2.6.24, you should just
append hpet=force to your kernel parameters.

>
> My a22m has a 900Mhz Mobile Pentium III with Speedstep according to  
> Thinkwiki. However, I tried to load cpufreq modules and the only one  
> that will load is speedstep-lib and I need one like speedstep-smi or  
> speedstep-ich to actually enable frequency scaling. The cpufreq  
> documentation says SOME PIII Coppermine processors will work but not  
> all. Is this one of the ones that has the primitive Speeedstep, in that  
> you can choose normal operating mode or power saving mode in the BIOS  
> and that's it? Because I tried the one that's optimized for battery life  

Just look into the lspci output. i830m chipsets have better speedstep
support. Boards based on the 440BX chipset are at bit limited here.

> and it does little to help. My battery life is about 4 hours but there  
> are still plenty of extra timer interrupts. If this is one of the  

What power consumption do you see in powertop? I get slightly below 10
Watts on my T23 when it is completely idle, LCD dimmed to the lowest
brightness, and hard disk spun down. Usually I get 10-12 Watts. I think
the A series is not as power efficient as the T series, so your numbers
might be somewhat higher.

Regards,
Tino