Date: Fri, 4 Jun 1999 12:30:03 -0700 (PDT) From: Chris Dillon <cdillon@wolves.k12.mo.us> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/12022: System clock timewarps Message-ID: <199906041930.MAA79278@freefall.freebsd.org>
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The following reply was made to PR kern/12022; it has been noted by GNATS. From: Chris Dillon <cdillon@wolves.k12.mo.us> To: dwhite@pond.net Cc: freebsd-gnats-submit@FreeBSD.ORG Subject: Re: kern/12022: System clock timewarps Date: Fri, 4 Jun 1999 14:20:11 -0500 (CDT) On Fri, 4 Jun 1999 dwhite@pond.net wrote: > I've also tried setting kern.timecounter.method=1 with no effect. > >How-To-Repeat: > . Find a PC. > . Boot 3.1 or later on it a few times. > . Watch the TSC go nuts. > >Fix: On the one 3.1+ (actually 3.2-STABLE) PIII-500 box I have here at work, TSC is extremely stable. Over 30 boots, I see it has ranged from 498830507 Hz to 498831075 Hz. I assume a total deviation of less than 1KHz (actually 568Hz, .000001% deviation) on a 500MHz clock is pretty darn stable. (Almost too stable... did I get that percentage right? I'm no statistician). I did experience just one time on my box at home a serious deviation, but overall it seems to be very stable. I don't have the actual figures from my box at home available right now, but ntpdate never adjusted the time more than about a couple of seconds a day until that one time the reported TSC was about 50% of the actual clockrate (Celeron 433), making the wall clock run extremely fast. -- Chris Dillon - cdillon@wolves.k12.mo.us - cdillon@inter-linc.net FreeBSD: The fastest and most stable server OS on the planet. For Intel x86 and Alpha architectures (SPARC under development). ( http://www.freebsd.org ) "One should admire Windows users. It takes a great deal of courage to trust Windows with your data." To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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