Ondemand vs. conservative governor

[Antti Mäkelä]

Hi all,

I tried out powertop. Seems to work and gives out expected results more 
or less on my Thinkpad (with i915 causing lots of wakeups). However...the 
tools gives me this

Suggestion: Enable the CONFIG_CPU_FREQ_GOV_ONDEMAND kernel configuration 
option. The 'ondemand' CPU speed governer will minimize the CPU power 
usage while giving you performance when it is needed.

I'm right now using "conservative" governor when computer goes to battery 
mode. The kernel docs (governors.txt) says

----
The CPUfreq governor "conservative", much like the "ondemand"
governor, sets the CPU depending on the current usage.  It differs in
behaviour in that it gracefully increases and decreases the CPU speed
rather than jumping to max speed the moment there is any load on the
CPU.  This behaviour more suitable in a battery powered environment.
----

   So, what is the basis for recommending "ondemand" instead of 
"conservative"? The kernel docs explicitly recommend "conservative" in 
battery environment instead of "ondemand".

   Thanks.

-- 
- Antti Mäkelä - http://www.cs.tut.fi/~zarhan - zarhan at cs.tut.fi -
There is a theory which states that if ever anyone discovers exactly
what the Universe is for and why it is here,it will instantly disappear
and be replaced by something even more bizarre and inexplicable.