Subject: Re: CVS commit: src/sys/kern
To: Izumi Tsutsui <tsutsui@ceres.dti.ne.jp>
From: Perry E. Metzger <perry@piermont.com>
List: source-changes
Date: 08/06/2006 00:36:56
Izumi Tsutsui <tsutsui@ceres.dti.ne.jp> writes:
> perry@piermont.com wrote:
>
>> Yes. It tells you how many Hz the clock source is supposed to be. The
>> clock itself will certainly have some inaccuracy, but it tells you
>> exactly what the spec is.
>
> How is such Hz value taken?
> i.e. doesn't the measuring method (i8254_delay()?) have inaccuracy?

I was under the impression that for some counters with fixed
frequency, like the ACPI time register, that the frequency was
determined by specification. Am I mistaken on that?

In any case, I prefer to know exactly what the value chosen is.

>>> timecounter: Timecounter "TSC" frequency 1300162690 Hz quality 800
>>> timecounter: Timecounter "TSC" frequency 1300166200 Hz quality 800
>>> timecounter: Timecounter "TSC" frequency 1300133700 Hz quality 800
>>> timecounter: Timecounter "TSC" frequency 1300126680 Hz quality 800
>>> timecounter: Timecounter "TSC" frequency 1300159180 Hz quality 800
>>> timecounter: Timecounter "TSC" frequency 1300128370 Hz quality 800
>>> timecounter: Timecounter "TSC" frequency 1300135390 Hz quality 800
>>> timecounter: Timecounter "TSC" frequency 1300171530 Hz quality 800
>>> timecounter: Timecounter "TSC" frequency 1300152420 Hz quality 800
>>> timecounter: Timecounter "TSC" frequency 1300130320 Hz quality 800
>>> timecounter: Timecounter "TSC" frequency 1300171140 Hz quality 800



-- 
Perry E. Metzger		perry@piermont.com