On Jun 8, 2007, at 2:08 PM, Martijn van Buul wrote:
>> It's likely that NetBSD uses the HLT instruction in the idle task to
>> reduce CPU power consumption; if you are talking about things like
>> PowerNow/SpeedStep-- AMD or Intel's capabilities (respectively) to
>> reduce the frequency that the CPU runs at if it is mostly idle, or
>> ACPI-based performance/throttling, I don't believe so.
>
> It does, at least in -current and 4.0beta2, but other OSes also  
> support the
> ACPI C-states. I don't think we do.

Thanks for the follow-up, Martijn.  I was doing some searching about  
this, and Google suggests that pages like:

    http://www.netbsd.org/changes/changes-4.0.html

...might say something about this, but all of the links at the top  
under:

    http://www.netbsd.org/changes/

...return 404 errors.

However, Google's cache thinks that you're right, and that:

    "Support Intel ICH-based SpeedStep(TM) in ichlpcib(4)  [mrg  
20040731]"

Trying a manpage lookup here:

    http://netbsd.gw.com/cgi-bin/man-cgi?ichlpcib

...returns no entries, so it's not clear where the actual status of  
SpeedStep support in NetBSD is documented.  :-)

-- 
-Chuck