Date: Tue, 16 Aug 2016 13:27:14 +0200 From: "Martin S. Weber" <Ephaeton@gmx.net> To: freebsd-questions@freebsd.org Subject: Re: Losing time like crazy (1s short per 10s) - how to investigate? Message-ID: <20160816112714.GA1241@hephaistos.local> In-Reply-To: <20160816112002.GA3083@hephaistos.local> References: <20160816112002.GA3083@hephaistos.local>
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On 2016-08-16 13:20:02, Martin S. Weber wrote: > This is on FreeBSD 10.3-RELEASE-p7. I've only noticed this today, > so I'd suspect this is post the p7 update (although I haven't > investigated in that direction yet). I'm losing roughly a second > per 10 seconds wall time. Look at this crazy guy: > > # ntpd -q ; sleep 10; ntpd -q > 16 Aug 13:12:52 ntpd[48425]: ntpd 4.2.8p8-a (1): Starting > (...) > 16 Aug 13:12:54 ntpd[48425]: ntpd: time set +0.891676 s > ntpd: time set +0.891676s > 16 Aug 13:13:04 ntpd[48426]: ntpd 4.2.8p8-a (1): Starting > (...) > 16 Aug 13:13:06 ntpd[48426]: ntpd: time set +1.218972 s > ntpd: time set +1.218972s > > This is a CRAZY amount of skew. I've never noticed this before -- > (...) Note, with (kernel) p4 (userland) p6 (I freebsd-update'd rollback) this does not happen: # ntpd -q ; sleep 10 ; ntpd -q 16 Aug 13:24:05 ntpd[1198]: ntpd 4.2.8p8-a (1): Starting 16 Aug 13:24:05 ntpd[1198]: Command line: ntpd -q 16 Aug 13:24:05 ntpd[1198]: proto: precision = 0.260 usec (-22) 16 Aug 13:24:05 ntpd[1198]: leapsecond file ('/var/db/ntpd.leap-seconds.list'): good hash signature 16 Aug 13:24:05 ntpd[1198]: leapsecond file ('/var/db/ntpd.leap-seconds.list'): loaded, expire=2016-12-28T00:00:00Z last=2015-07-01T00:00:00Z ofs=36 16 Aug 13:24:05 ntpd[1198]: Listen and drop on 0 v6wildcard [::]:123 16 Aug 13:24:05 ntpd[1198]: Listen and drop on 1 v4wildcard 0.0.0.0:123 16 Aug 13:24:05 ntpd[1198]: Listen normally on 2 em0 10.10.1.79:123 16 Aug 13:24:05 ntpd[1198]: Listen normally on 3 lo0 [::1]:123 16 Aug 13:24:05 ntpd[1198]: Listen normally on 4 lo0 [fe80::1%2]:123 16 Aug 13:24:05 ntpd[1198]: Listen normally on 5 lo0 127.0.0.1:123 16 Aug 13:24:05 ntpd[1198]: Listening on routing socket on fd #26 for interface updates 16 Aug 13:24:06 ntpd[1198]: ntpd: time slew +0.008026 s ntpd: time slew +0.008026s 16 Aug 13:24:16 ntpd[1201]: ntpd 4.2.8p8-a (1): Starting 16 Aug 13:24:16 ntpd[1201]: Command line: ntpd -q 16 Aug 13:24:16 ntpd[1201]: proto: precision = 0.255 usec (-22) 16 Aug 13:24:16 ntpd[1201]: leapsecond file ('/var/db/ntpd.leap-seconds.list'): good hash signature 16 Aug 13:24:16 ntpd[1201]: leapsecond file ('/var/db/ntpd.leap-seconds.list'): loaded, expire=2016-12-28T00:00:00Z last=2015-07-01T00:00:00Z ofs=36 16 Aug 13:24:16 ntpd[1201]: Listen and drop on 0 v6wildcard [::]:123 16 Aug 13:24:16 ntpd[1201]: Listen and drop on 1 v4wildcard 0.0.0.0:123 16 Aug 13:24:16 ntpd[1201]: Listen normally on 2 em0 10.10.1.79:123 16 Aug 13:24:16 ntpd[1201]: Listen normally on 3 lo0 [::1]:123 16 Aug 13:24:16 ntpd[1201]: Listen normally on 4 lo0 [fe80::1%2]:123 16 Aug 13:24:16 ntpd[1201]: Listen normally on 5 lo0 127.0.0.1:123 16 Aug 13:24:16 ntpd[1201]: Listening on routing socket on fd #26 for interface updates 16 Aug 13:24:17 ntpd[1201]: ntpd: time slew +0.007526 s ntpd: time slew +0.007526s So, jumping to conclusions, p6->p7 makes all the difference. This is the skew since starting to write THIS email: 16 Aug 13:26:26 ntpd[1251]: ntpd: time slew -0.005940 s Looks way more reasonable to me. Time to PR? Regards, -Martin
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