ACPI-fast default timecounter, but HPET 83% faster

Bruce Cran bruce at
Thu Apr 30 21:52:52 UTC 2009

On Thu, 30 Apr 2009 08:46:41 -0400
John Baldwin <jhb at> wrote:

> On Sunday 26 April 2009 10:27:42 pm Garrett Cooper wrote:

> > Why's the default ACPI-fast? For power-saving functionality or
> > because of the `quality' factor? What is the criteria that
> > determines the `quality' of a clock as what's being reported above
> > (I know what determines the quality of a clock visually from a
> > oscilloscope =])?
> I suspect that the quality of the HPET driver is lower simply because
> no one had measured it previously and HPET is newer and less "proven".
shows some of the history behind the decision.  Apparently it used to
be slower but it was hoped it would get faster as systems supported it
better. I guess that's happening now.

Bruce Cran

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