From owner-freebsd-questions Wed Apr 12 1: 6:27 2000 Delivered-To: freebsd-questions@freebsd.org Received: from maxim.gba.oz.au (gba.tmx.com.au [203.9.155.249]) by hub.freebsd.org (Postfix) with SMTP id 06CF337B5A8 for ; Wed, 12 Apr 2000 01:06:19 -0700 (PDT) (envelope-from gjb-freebsd@gba.oz.au) Received: (qmail 15274 invoked by uid 1001); 12 Apr 2000 07:12:06 +1000 X-Posted-By: GBA-Post 2.02.01 12-Dec-1999 X-PGP-Fingerprint: 5A91 6942 8CEA 9DAB B95B C249 1CE1 493B 2B5A CE30 Message-Id: Date: Wed, 12 Apr 2000 07:12:05 +1000 From: Greg Black To: FreeBSD-questions@FreeBSD.ORG Subject: Re: Kernel adjustment for clock drift References: In-reply-to: of Thu, 06 Apr 2000 20:09:50 +1000 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG About a week ago I wrote: > I've been away from the lists for ages and am looking for an > update on clock drift management under FreeBSD-3.4R. I have a > machine that drifts about 7 seconds a day and I'd like to tweak > something in the kernel to keep it closer to the truth. The > clock gets corrected once a day by ntpdate, but I'd like to > avoid such big adjustments. For the benefit of anybody who wanted to know the answer, I got the following very helpful response from Poul-Henning Kamp (also posted on -hackers): On 3.4 you need to set the frequency of the relevant timecounter. If you grep Timecounter /var/run/dmesg.boot and look at the *last line*, it will say either TSC or i8254. You can then modify the frequency with the corresponding sysctl variable: machdep.i8254_freq: 1193182 or machdep.tsc_freq: 400911216 and set the frequency there. Make sure that you have APM firmly disabled in the BIOS. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message