Date: Tue, 21 Nov 2000 12:08:03 -0800 (PST) From: "Thomas D. Dean" <tomdean@ix.netcom.com> To: current@FreeBSD.ORG Subject: Re: Clock Strangeness in UP Kernel Message-ID: <200011212008.eALK83E00524@ix.netcom.com> In-Reply-To: <200011200212.eAK2Cj500371@ix.netcom.com> (tomdean@ix.netcom.com) References: <200011200212.eAK2Cj500371@ix.netcom.com>
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I have a high clock drift rate. The problem is in selecting the timecounter, at least on my machine. Both the TSC and the i8254 timecounters are checked and, since, I believe, TSC is last, TSC is the timecounter the kernel uses. TSC is a horrible timer, at least on my machine. i8254 is not perfect, but several orders of magnitude better, at least with FreeBSD. # sysctl -a ... kern.timecounter.hardware: TSC ... # sysctl -w kern.timecounter.hardware=i8264 fixes the clock drift. Now, it is less than 2 seconds per 4 hours. And, that is well within the range ntp can satisfactorily correct for. tomdean To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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