From owner-freebsd-questions Sun Feb 21 14:56:50 1999 Delivered-To: freebsd-questions@freebsd.org Received: from mail.greatbasin.net (mail.greatbasin.net [207.228.35.39]) by hub.freebsd.org (Postfix) with ESMTP id 6F65D11572 for ; Sun, 21 Feb 1999 14:56:44 -0800 (PST) (envelope-from dan@jgl.reno.nv.us) Received: from pandora.home (jgl.reno.nv.us [207.228.2.142]) by mail.greatbasin.net (8.9.2/8.8.8) with ESMTP id OAA15056 for ; Sun, 21 Feb 1999 14:56:43 -0800 (PST) Received: from danco (danco.home [10.0.0.2]) by pandora.home (8.9.2/8.9.2) with SMTP id OAA00263 for ; Sun, 21 Feb 1999 14:56:41 -0800 (PST) (envelope-from dan@jgl.reno.nv.us) Message-ID: <01f501be5ded$7278bc20$0200000a@danco.home> From: "Dan O'Connor" To: "freebsd-questions" Subject: Q: Timecounter "TSC" and drifting clock and calcru neg time Date: Sun, 21 Feb 1999 14:56:40 -0800 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3155.0 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3155.0 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Good Sunday, everyone, I'm running 3.1-STABLE on a Pentium 90 machine. I have a clock that drifts badly (fast by almost 2 min per hour), although after some reboots, it drifts just a few seconds per hour. Occasionally after a reboot, I'll get 'calcru negative time' messages. I've traced this problem to the following symptom: During boot, the line Timecounter "TSC" frequency xxxxxxxxx Hz is displayed. The routine that clocks the system seems more like a random number generator, and I've seen the following values: 90.2 MHz 87.7 MHz 77.5 MHz At 90.2 MHz, the system clock is pretty accurate. At 87.7 MHz, the clock runs fast by over 90 seconds per hour. (And 90MHz / 87.7 MHz * 3600 - 3600 = +94 seconds per hour, imagine that!) At 77.5 MHz, the 'calcru negative time' errors pop up. I know that, as reported on this list, the timekeeping code is broken, but my question is this: Is there somewhere I can tell the system to use a TSC frequency of 90000000 Hz and have it skip it's internal calibration? I don't envision changing CPUs too often, so I'm not worried about hardcoding it... --Dan ** The thing I like most about Windows 98 is... ** You can download FreeBSD with it! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message