Le 2012/02/18 22:50, Darren New a écrit :
> On 2/7/2012 19:44, Alain wrote:
>> A good example of something that can use the CPU at 100% and don't
>> generate
>> heat is the "idle process" that is only a small loop...
>
> Idle processes haven't actually run the CPU for decades. The idle
> process isn't a loop - it turns off the clock.
>

It can only do that IF you can effectively dynamicaly alter the clock speed.
At least on my computer, it's just not possible, and it's not decades 
old... just about 11 years old. I don't say for the actual 64 bits CPUs, 
but, for 32 bits ones, most just can't have the clock turned OFF, as it 
was not software controled, but a static setting that could only be set 
via the BIOS.


Alain

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On 2/27/2012 14:08, Alain wrote:
> Le 2012/02/18 22:50, Darren New a écrit :
>> On 2/7/2012 19:44, Alain wrote:
>>> A good example of something that can use the CPU at 100% and don't
>>> generate
>>> heat is the "idle process" that is only a small loop...
>>
>> Idle processes haven't actually run the CPU for decades. The idle
>> process isn't a loop - it turns off the clock.
>>
>
> It can only do that IF you can effectively dynamicaly alter the clock s
peed.

http://en.wikipedia.org/wiki/HLT

It's not literally turning off the clock, of course. But the "idle proces
s" 
is not sitting there looping while it's idle. Yes, the idle process loops
, 
but it only loops once per processor schedule. If the machine sits there 
for 
3 seconds without an interrupt, it'll still only run a handful of instruc
tions.

-- 
Darren New, San Diego CA, USA (PST)
   People tell me I am the counter-example.

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