[ltp] T61 temperature limits

[Henrique de Moraes Holschuh]

On Wed, 16 Apr 2008, Richard Neill wrote:
> In desktop mode, the limit is the CPU. I don't know what the values are,

Ignore the other sensors, and your thinkpad will fry.  You have been
warned.

> but I'd expect 100 degrees to be perfectly safe for the chip. Someone
> with more knowledge will need to comment here.

The CPU itself might be okay, but the rest of the thinkpad might not be
if you let the heat build up too much in the vicinity of the CPU, OR in
the heat sink itself.

> P.S. You might also consider using nice to make CPU-hogging processes
> not use so much power

Nice alone can't do that.  You want a process to use less power?  Let it
end (or sleep) as quickly as possible so that the CPU can go to C3
("race to idle").  If it is a long running process where "race to idle"
doesn't matter (i.e. it doesn't sleep, for example), you either stop it
for a while and then let it run again for another while (using
SIGSTOP/SIGCONT for example), or you use nice and tell the cpu speed
governor to ignore niced loads.

SIGSTOP+SIGCONT will probably waste less power, but you'd have to
measure it to know, as that depends on the workload and also on just how
much time in C3 your CPU will stay when the background process is not
running.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh