wrong kern.boottime

[Cyrille Lefevre]

"Poul-Henning Kamp" wrote:


> In message <06ef01c3ebdd$36b53190$7890a8c0 at dyndns.org>, "Cyrille Lefevre"
write
> s:
>
> >> ># last reboot
> >> >reboot           ~                         Sun Feb  1 21:41
> >> ># ls -l /var/run/dmesg.boot
> >> ><
> >> >-rw-r--r--  1 root  wheel  5547 Feb  1 21:40 /var/run/dmesg.boot
> >> ># sysctl kern.boottime
> >> >kern.boottime: { sec = 1075812223, usec = 350585 } Tue Feb  3 13:43:43
2004
> >> ># uname -a
> >> >FreeBSD gits 5.2-CURRENT FreeBSD 5.2-CURRENT #1: Sat Jan 31 15:17:05 CET
2004
> >> >
> >> >any idea ?
> >>
> >> What does "date" say on your machine ?
> >
> ># date -u
> >Thu Feb  5 11:39:36 UTC 2004
> ># date
> >Thu Feb  5 12:39:39 CET 2004
> ># ls -l /etc/wall_cmos_clock
> >-rw-r--r--  1 root  wheel  0 Jun  9  2001 /etc/wall_cmos_clock
> >
> >ntpd is running, so, I'm on time.
>
> Hmm, I'm not sure where last gets it's number from, maybe from utmp.

no, from wtmp.

> If the utmp record is written on boot before ntpd corrects the clock
> that would be one explanation...
>
> Either way, I'm pretty sure that kern.boottime contains what it should
> contain:  Our best estimate of the time when the system was booted.

absolutely not, the real boot time was the wtmp time which is the same
as /var/run/dmesg.boot.

a proof of the real boot time :

# bzgrep Accounting /var/log/messages.*
messages.2.bz2:Feb  1 21:40:43 <kern.notice> gits kernel: Accounting enabled


I forgot to give you what uptime says...

# uptime
 1:35PM  up 1 day, 14:04, 2 users, load averages: 3.56, 4.63, 5.17

as well as snmpget :

# snmpget -v2c -c public localhost HOST-RESOURCES-MIB::hrSystemUptime.0
HOST-RESOURCES-MIB::hrSystemUptime.0 2:22:59:31.12

Cyrille Lefevre.
-- 
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