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Date:      Thu, 6 Feb 2003 11:19:40 +1030
From:      Greg 'groggy' Lehey <grog@FreeBSD.org>
To:        Poul-Henning Kamp <phk@FreeBSD.org>
Cc:        all-committers@FreeBSD.org, legacy-committers@FreeBSD.org, cvs-all@FreeBSD.org
Subject:   Re: cvs commit: src/sys/i386/include clock.h src/sys/i386/i386 tsc.c
Message-ID:  <20030206004940.GH26321@wantadilla.lemis.com>
In-Reply-To: <200302050920.h159KeQ1048771@repoman.freebsd.org>
References:  <200302050920.h159KeQ1048771@repoman.freebsd.org>

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On Wednesday,  5 February 2003 at  1:20:40 -0800, Poul-Henning Kamp wrote:
> phk         2003/02/05 01:20:40 PST
>
>   Modified files:
>     sys/i386/include     clock.h
>     sys/i386/i386        tsc.c
>   Log:
>   i386/i386/tsc.c was repo-copied from i386/isa/clock.c.
>
>   Remove all the stuff that does not relate to the TSC.
>
>   Change the calibration to use DELAY(1000000) rather than trying to check
>   it against the CMOS RTC, this drastically increases precision:
>
>   Using 25 samples on a Athlon 700MHz UP machine I find:
>
>                   stddev          min          max        average
>   CMOS             22200 Hz    -74980 Hz     34301 Hz   704928721 Hz
>   DELAY             1805 Hz     -1984 Hz      2678 Hz   704937583 Hz
>
>   (The difference between the two averages is not statistically significant.)

Does this get rid of the "microuptime went backwards" problem?

Greg
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