Date: Wed, 12 Mar 2014 12:26:35 -0700 (PDT) From: Anton Shterenlikht <mexas@bris.ac.uk> To: cswiger@mac.com, mexas@bris.ac.uk Cc: freebsd-questions@freebsd.org Subject: Re: ntp frequent time resets - battery dead? Message-ID: <201403121926.s2CJQXbQ078112@mech-cluster241.men.bris.ac.uk> In-Reply-To: <339ED6B9-F04D-4812-B228-729696C64E47@mac.com>
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>From cswiger@mac.com Tue Mar 4 20:51:34 2014 > >Hi-- > >On Mar 4, 2014, at 1:07 AM, Anton Shterenlikht <mexas@bris.ac.uk> wrote: >> I see in /var/log/messages: >> >> Mar 4 00:16:40 mech-anton240 ntpd[764]: time reset +0.291030 s >> Mar 4 00:38:02 mech-anton240 ntpd[764]: time reset +0.344745 s >> Mar 4 00:57:37 mech-anton240 ntpd[764]: time reset +0.338739 s >> Mar 4 01:19:45 mech-anton240 ntpd[764]: time reset +0.355020 s >> Mar 4 01:41:34 mech-anton240 ntpd[764]: time reset +0.365177 s >> Mar 4 01:58:41 mech-anton240 ntpd[764]: time reset +0.306982 s >> >> and so on. >> >> The correction seems large to me. > >Yes, it looks to be about ~1 second per hour. That's 1:1000 ratio, >which is getting close to the typical kernel limit on adjtime(). > >Tweaking the step threshold might help. Or look into tickadj / ntptime. Sorry, I don't understand this. Please elaborate. > >> Does this indicate that the battery is dead? > >A dead battery usually means that the system won't keep the ToY clock updated >if the system is off and unplugged. A PC would indicate BIOS checksum errors >and reset the ToY clock back to epoch. I think Suns of that era were still >using OpenFirmware on EEPROMS which didn't need power to keep their settings. > >> This is on a Sun Blade 1500 silver desktop, about 10 years old. > >Having the clock run slow (ie, needing the time to be moved forwards) can >result from interrupt handling issues; if something like a USB controller, or >storage controller, etc is wonky and generating thousands of interrupts per >second, the ISR being busy might cause clock interrupts to be lost because >the kernel is otherwise busy. > >That ought to be more common on commodity Intel hardware than on SPARCs; as the >SPARC v8 and later had several levels of nested interrupt contexts available, IIRC. > >Regards, >-- >-Chuck I had suspected disk problems on this box, so I replaced both disks, and installed 9.1 release. The problem actually got worse: Mar 12 15:19:39 mech-aslap33 kernel: Event timer "tick" frequency 1503000000 Hz quality 1000 Mar 12 15:34:01 mech-anton240 kernel: Event timer "tick" frequency 1503000000 Hz quality 1000 Mar 12 15:34:13 mech-anton240 ntpd[706]: time reset -1.086763 s Mar 12 15:50:45 mech-anton240 ntpd[706]: time reset +0.780002 s Mar 12 16:08:45 mech-anton240 ntpd[706]: time reset +0.816043 s Mar 12 16:26:20 mech-anton240 ntpd[706]: time reset +0.788435 s Mar 12 16:43:03 mech-anton240 ntpd[706]: time reset +0.774967 s Mar 12 17:00:24 mech-anton240 ntpd[706]: time reset +0.792823 s Mar 12 17:17:53 mech-anton240 ntpd[706]: time reset +0.786167 s Mar 12 17:34:22 mech-anton240 ntpd[706]: time reset +0.769774 s Mar 12 17:51:34 mech-anton240 ntpd[706]: time reset +0.787633 s Mar 12 18:08:29 mech-anton240 ntpd[706]: time reset +0.766031 s Mar 12 18:25:40 mech-anton240 ntpd[706]: time reset +0.786657 s Mar 12 18:42:47 mech-anton240 ntpd[706]: time reset +0.762096 s Mar 12 19:00:56 mech-anton240 ntpd[706]: time reset +0.813446 s Note that after every reboot, there is a large negative correction, then about 2 sec per hour. So this indeed looks like some hardware issue, rather that an OS problem. Thanks Anton > >
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