Date: Wed, 01 May 2002 16:25:48 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Daniel Rock <D.Rock@t-online.de> Cc: current@FreeBSD.ORG Subject: Re: clock drift in -CURRENT Message-ID: <64858.1020263148@critter.freebsd.dk> In-Reply-To: Your message of "Wed, 01 May 2002 13:49:08 %2B0200." <3CCFD634.6F7D20B1@t-online.de>
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When was your source tree from on that kernel ? I'm not too confident in your diagnosis, mostly because we don't have a counter like you describe :-) My guess is that ntpd get confused. Please try a newer kernel, a number of bug(lets) have been fixed since march. If it happens again, please email me the output of: ntpdc -c peer ntpdc -c loopi ntpdc -c kerni dmesg Thanks! Poul-Henning In message <3CCFD634.6F7D20B1@t-online.de>, Daniel Rock writes: >Hi, > >after almost 50 days of uptime I suddenly noticed an extreme clock drift >in current. Here is an excerpt from my /var/log/messages (March 8th was my >last reboot time): > >Mar 8 18:38:07 gate syslogd: kernel boot file is /boot/kernel/kernel >Mar 8 18:38:07 gate kernel: Copyright (c) 1992-2002 The FreeBSD Project. >[...] >Apr 27 20:03:10 gate ntpd[157]: time reset -0.250532 s >Apr 27 20:18:14 gate ntpd[157]: time reset 0.446208 s >Apr 27 20:39:57 gate ntpd[157]: time reset -0.820100 s >Apr 27 21:11:19 gate ntpd[157]: time reset 0.887949 s >Apr 27 21:25:33 gate ntpd[157]: time reset -0.228488 s >Apr 27 21:54:35 gate ntpd[157]: time reset -0.395676 s >Apr 28 12:59:15 gate ntpd[157]: time reset -0.381327 s >Apr 28 13:19:52 gate ntpd[157]: time reset 0.815323 s >Apr 28 13:31:50 gate ntpd[157]: time reset 0.844171 s >Apr 28 13:58:52 gate ntpd[157]: time reset 1.447538 s >Apr 28 14:14:58 gate ntpd[157]: time reset 0.915263 s >Apr 28 14:36:38 gate ntpd[157]: time reset 0.860966 s >Apr 28 14:47:29 gate ntpd[157]: time reset 0.984839 s >Apr 28 15:06:59 gate ntpd[157]: time reset 1.025584 s >Apr 28 15:27:32 gate ntpd[157]: time reset 1.156623 s >Apr 28 15:48:59 gate ntpd[157]: time reset 0.896726 s >Apr 28 16:00:52 gate ntpd[157]: time reset 0.973291 s >Apr 28 16:24:24 gate ntpd[157]: time reset 1.212415 s >Apr 28 16:37:19 gate ntpd[157]: time reset 0.859379 s >Apr 28 16:56:49 gate ntpd[157]: time reset 0.914863 s >Apr 28 17:13:05 gate ntpd[157]: time reset 1.100234 s >Apr 28 17:35:59 gate ntpd[157]: time reset 1.231416 s >Apr 28 17:59:53 gate ntpd[157]: time reset 1.026558 s >Apr 28 18:11:59 gate ntpd[157]: time reset 0.995554 s >Apr 28 18:34:45 gate ntpd[157]: time reset 1.140261 s >Apr 28 18:54:19 gate ntpd[157]: time reset 0.856611 s >Apr 28 19:07:15 gate ntpd[157]: time reset 1.094226 s >Apr 28 19:22:30 gate ntpd[157]: time reset 0.879816 s >Apr 28 19:47:25 gate ntpd[157]: time reset 1.332108 s >Apr 28 20:06:56 gate ntpd[157]: time reset 0.949128 s >Apr 28 20:28:27 gate ntpd[157]: time reset 0.906657 s >Apr 28 20:41:37 gate ntpd[157]: time reset 0.877976 s >Apr 28 20:57:57 gate ntpd[157]: time reset 1.103012 s >Apr 28 21:28:19 gate ntpd[157]: time reset 1.607870 s >Apr 28 21:59:43 gate ntpd[157]: time reset 1.253603 s >Apr 28 22:14:46 gate ntpd[157]: time reset 1.181729 s >Apr 28 22:47:13 gate ntpd[157]: time reset 1.573263 s >Apr 28 23:07:47 gate ntpd[157]: time reset 0.836291 s >Apr 28 23:20:52 gate ntpd[157]: time reset 1.105955 s >Apr 28 23:35:59 gate ntpd[157]: time reset 0.839469 s >[...] > >So the machine is losing a second every 20 minutes. After a reboot everything >was OK again. > >The drift began exactly at the moment the counter for clock interrupts got >past the 2^31 mark (I have HZ=500 in the kernel): >500 ticks/s * 49.7 days ~ 2^31 ticks > >After a reboot everything went ok again. > >To Unsubscribe: send mail to majordomo@FreeBSD.org >with "unsubscribe freebsd-current" in the body of the message > -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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