Date: Thu, 15 May 2008 22:37:28 +0200 From: Volker Jahns <volker@thalreit.de> To: Volker Jahns <volker@thalreit.de> Cc: freebsd-questions@freebsd.org Subject: Re: time drift Message-ID: <20080515203728.GA14284@ikarus.thalreit> In-Reply-To: <20080515195302.GA13531@ikarus.thalreit> References: <20080515185758.GA12709@ikarus.thalreit> <597571FB-C72D-4603-B379-A59A435843BE@mac.com> <20080515195302.GA13531@ikarus.thalreit>
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On Thu, May 15, 2008 at 09:53:02PM +0200, Volker Jahns wrote: > On Thu, May 15, 2008 at 12:18:57PM -0700, Chuck Swiger wrote: > > On May 15, 2008, at 11:57 AM, Volker Jahns wrote: > > >FreeBSD 6.2 running on X86 hardware (FSC) shows a remarkable time > > >drift > > > > > >running ntpdate every half hour shows that the system looses about > > >10-14 sec each time. > > >15 May 10:06:48 ntpdate[7200]: step time server 192.53.103.108 > > >offset -13.799602 sec > > >15 May 10:36:48 ntpdate[7515]: step time server 192.53.103.108 > > >offset -12.813941 sec > > >15 May 11:06:48 ntpdate[7879]: step time server 192.53.103.108 > > >offset -13.651921 sec > > >15 May 11:36:50 ntpdate[8079]: step time server 192.53.103.108 > > >offset -11.109298 sec > > >15 May 12:06:50 ntpdate[8289]: step time server 192.53.103.108 > > >offset -11.836499 sec > > > > You should also take a look at the output of "sysctl > > kern.timecounter", and possibly switch to a different mechanism, if > > the existing choice doesn't work out well for your machine... > Thanks for the hint. A few years ago a time drift problem had been observed by a German freebsd user (http://www.freebsd.de/rachive/de-bsd-questions.200304/0643.html). Time drift 15 sec every half hour, ntpd dies away running on his machine. Setting kern.timecounter.hardware to TSC had been recommended as a solution. -- Volker Jahns, volker@thalreit.de
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