machdep.cpu_idle_hlt on a Dual AMD 2000+ MP

[Jesper Skriver]

On Sun, Apr 27, 2003 at 07:35:39PM +0100, Peter Wood wrote:
> Afternoon,
> 
> I was reading all the threads regarding hyperthreading, and descovered that
> machdep.cpu_idle_hlt is set to 0 by default on SMP machines and 1 on
> uniprocessor machines.
> 
> I've change it to 1 on my dual machine, and so far it appears stable. I have
> noticed that the CPU tempratures appear to be lower now, possibly a
> coincidence as the servers load may have been changing. Should I expect it to
> be lower?

Yes, you should expect the temperature and power usage to be lower.

> Also should I expect to see any performance loss, or instability? Does anyone
> know the original reason for setting the defaults this way?

There is a slight performance loss on SMP systems, this is the reason
for the default.

/Jesper

-- 
Jesper Skriver, jesper(at)skriver(dot)dk  -  CCIE #5456

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