Date: Sun, 21 Feb 1999 14:56:40 -0800 From: "Dan O'Connor" <dan@jgl.reno.nv.us> To: "freebsd-questions" <freebsd-questions@freebsd.org> Subject: Q: Timecounter "TSC" and drifting clock and calcru neg time Message-ID: <01f501be5ded$7278bc20$0200000a@danco.home>
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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
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