Re: wrong estd value

["Steven M. Bellovin" <smb%cs.columbia.edu@localhost>]

On Sat, 30 Aug 2008 12:16:57 +0100
Matthias Scheler <tron%zhadum.org.uk@localhost> wrote:

> 
> On 30 Aug 2008, at 11:38, Joel CARNAT wrote:
> > My Dell XPS M1330 has a "Intel(R) Core(TM)2 Duo CPU     T7300  @  
> > 2.00GHz"
> > CPU.
> > But sysctl reports 2200 MHz option for machdep.est.frequency:
> > machdep.est.frequency.target = 1200
> > machdep.est.frequency.current = 1200
> > machdep.est.frequency.available = 2200 2000 1800 1600 1400 1200
> 
> 
> That's correct. Intel calls this feature "Enhanced Dynamic  
> Acceleration Technology".
> It allows to overclock the CPU if only one core is active.
> 
>       Kind regards
> 
> P.S. This really belongs on "port-i386%NetBSD.org@localhost".
> 
And port-amd64, since I see the same issue...  I've redirected this
follow-up to those lists.

My question is this: is this a pure hardware feature, or do we need to
do something to support this properly?  For example -- given my usage
pattern, the primary time I'm running at max CPU speed for an extended
period is when I'm doing a system build, which I do with -j3.  That, of
course, means that both CPUs will be running flat-out.  What speed is
it really running at?  Like Joel, I've opted to use -M to cap the
speed, for fear of overheating the chip.  Am I being too cautious?


                --Steve Bellovin, http://www.cs.columbia.edu/~smb