How can this 'top' command output make sense? Load over 7 and
total CPU use ~5%
wojtek at wojtek.tensor.gdynia.pl
Mon May 25 22:44:30 UTC 2009
>> performing at 100%...
> While it's not the default behaviour, if you run powerd(8) then
> yes, the CPU will run slower when it's less utilized.
that's extra,and very useful option.
anyway even without that modern processor gets MUCH less power just when
being halted by hlt instruction. there is still some power used for clock
network within chip, and gate oxide leakage, but
almost no other gate switching.
just using hlt takes down power usage to 1/3-1/5 of full power.
reducing clock with turn it down even more.
i'm not sure but turning modern processors on lower speed this way
(powerd) change voltage down too a bit which even reduces leakage.
anyway powerd didn't work well on my laptop last time i tried, but it was
with FreeBSD 6, maybe something changed - i will try this. maybe it will
add some 10-20 minutes more battery life.
anyway lots of power is used by my UMTS modem, and i can't disconnect it
as i usually do need the net while using laptop.
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