[ltp] Re: Re: Stress testing for undervolting

[TNKS]

Laurent Gilson wrote:

> First i searched the absolute minimum voltage for each frequency by
> running mprime and decreasing the voltage by 1 step every 10 seconds. That
> way i found the drop-off points (and crashed/rebooted 2-3 times).
> Afterwards i increased every voltage by 1 step (2 for the ones that
> crashed hard).

Yeah... that's about as far as I've gotten (the easy part).
 
> Then 2 hours torture test with all the things i wrote in the first mail
> (mprime, seeks, WLAN, changing the frequency via script every 30 sec). No
> crashs, no error in mprime. But it still didn´t "feel" safe so i added
> another step to each voltage.

Do you still have this script?  It might be interesting to see it
explicitly.  
In your first post you mentioned that you unplugged/replugged the AC and the 
battery.  Did you do that physically/manually?  Or could you do it "soft"
via 
a script?

> 
> After 3 hours surfing/office my CPU is at 42-45°C, w/o any fan running. I
> have 3:45 runtime from a 40Wh battery (with WLAN switched on but bluetooth
> off) (IBM promises 3:00 for a 47Wh... go figure). I didn´t bother to check
> if the last "safety" step was really necessary.

That's nice.  I'm curious.  It sounds as though you're about as careful with 
under-volting as I would like to be.  Did you try to dig a little more power 
conservation by messing with the fan speeds/triggers?  I'm really 
apprehensive to go so far.  It seems to me that if temperatures are really 
lower, then fan usage should drop without any further tinkering.  For now, 
I'm just leaving the fan as is.

-Sukant