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Date:      Sat, 28 Feb 1998 08:27:42 +0200 (SAT)
From:      John Hay <jhay@mikom.csir.co.za>
To:        mark@vmunix.com (Mark Mayo)
Cc:        current@FreeBSD.ORG
Subject:   Re: I586_CALIBRATION ??
Message-ID:  <199802280627.IAA05667@zibbi.mikom.csir.co.za>
In-Reply-To: <19980227232116.35376@vmunix.com> from Mark Mayo at "Feb 27, 98 11:21:16 pm"

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> Hi, just curious where CLK_USE_I586_CALIBRATION went ??
> 
> I used to use in my PPro, but not config (and LINT) tell me
> it's no longer an option. With the I586_CALIBRATION the boot
> message would correctly detect the CPU speed each and every
> time. Now it's off by +/- 15%, and my clock has gained over
> an hour in under a day.. :-(
> 
> What should I be using here?? I have the 
> CLK_USE_I8254_CALIBRATION option in the kernel right now. Maybe I
> should have nothing "extra" in there?

It is now called CLK_USE_TSC_CALIBRATION :-) It is being used on
Pentium and better processors except SMP machines. 486 and below
and SMP machines use the I8254 variation. You can define both in
a kernel config file and the system will figure out which to use.

Defining CLK_USE_TSC_CALIBRATION made a huge difference on my
machine's clock here.

Well that is my understanding...

John
-- 
John Hay -- John.Hay@mikom.csir.co.za

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