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Groups > linux.debian.user > #198598

Re: What time is it, really?

From Michael Stone <mstone@debian.org>
Newsgroups linux.debian.user
Subject Re: What time is it, really?
Date 2018-08-10 23:00 +0200
Message-ID <wlmFQ-4J1-13@gated-at.bofh.it> (permalink)
References (5 earlier) <wkZ6y-7BJ-3@gated-at.bofh.it> <wl0OZ-ht-3@gated-at.bofh.it> <wlhmN-1ME-1@gated-at.bofh.it> <wliCd-2pT-1@gated-at.bofh.it> <wljHY-31t-3@gated-at.bofh.it>
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On Fri, Aug 10, 2018 at 07:46:46PM +0200, Fekete Tamás wrote:
>verify the output. note: ntpd has to run!). Assume, that you choosed the proper
>time source for sync, so it means that the mechanism which steps your clock
>locally is broken. It can be battery reasons on the mainboard, temperature can
>also influence (but not too much nowadays), if you use virtual machine, that
>matters a lot, as it gets the CPU cycles from the host machine, and it's inner
>time stepping highly depends on the CPU time given by the host, finally I have
>never read anything about the effect of overclocking the CPU, it might have
>also effect on this, but test should be run to be sure.

It's also really bad to run more than one time synchronization at 
once--they'll tend to confuse each other and cause random time shifts.

>Ntpd has higher threshold to step the clock.
>"After some time, small offsets (significantly less than a second) will be
>slewed (adjusted slowly), while larger offsets will cause the clock to be
>stepped (set anew)."
>Source: http://www.ntp.org/ntpfaq/NTP-s-algo.htm

This isn't true on ntpd startup; it'll step the clock to get it close 
and slew thereafter. The only case where this a problem is if there are 
major issues with the local clock. (Which generally means you have 
bigger problems.) You may be thinking of the behavior where ntpd will 
exit on startup if the time is too far off. Using the -g option causes 
it to just set the time and carry on. (There are pros and cons to both 
approaches.)

Mike Stone

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Thread

What time is it, really? Fred <fred@blakemfg.com> - 2018-08-09 16:40 +0200
  Re: What time is it, really? Martin <keine-eile@online.de> - 2018-08-09 16:40 +0200
  Re: What time is it, really? Greg Wooledge <wooledg@eeg.ccf.org> - 2018-08-09 16:40 +0200
    Re: What time is it, really? Jim Popovitch <jim@k4vqc.com> - 2018-08-09 17:00 +0200
      Re: What time is it, really? Greg Wooledge <wooledg@eeg.ccf.org> - 2018-08-09 17:10 +0200
        Re: What time is it, really? Jim Popovitch <jim@k4vqc.com> - 2018-08-09 17:10 +0200
        Re: What time is it, really? john doe <johndoe65534@mail.com> - 2018-08-09 20:40 +0200
          Re: What time is it, really? Brian <ad44@cityscape.co.uk> - 2018-08-09 21:50 +0200
            Re: What time is it, really? Fred <fred@blakemfg.com> - 2018-08-09 23:40 +0200
              Re: What time is it, really? Shea Alterio <krusete@gmail.com> - 2018-08-10 00:00 +0200
              Re: What time is it, really? David Wright <deblis@lionunicorn.co.uk> - 2018-08-10 17:20 +0200
                Re: What time is it, really? Michael Stone <mstone@debian.org> - 2018-08-10 17:40 +0200
                Re: What time is it, really? David Wright <deblis@lionunicorn.co.uk> - 2018-08-10 21:50 +0200
                Re: What time is it, really? Fred <fred@blakemfg.com> - 2018-08-10 18:40 +0200
                Re: What time is it, really? Brian <ad44@cityscape.co.uk> - 2018-08-10 19:50 +0200
                Re: What time is it, really? Fekete Tamás <fektom@gmail.com> - 2018-08-10 19:50 +0200
                Re: What time is it, really? Greg Wooledge <wooledg@eeg.ccf.org> - 2018-08-10 20:10 +0200
                Re: What time is it, really? Gene Heskett <gheskett@shentel.net> - 2018-08-10 20:20 +0200
                Re: What time is it, really? Michael Stone <mstone@debian.org> - 2018-08-10 23:00 +0200
                Re: What time is it, really? Fekete Tamás <fektom@gmail.com> - 2018-08-11 11:10 +0200
                Re: What time is it, really? David Wright <deblis@lionunicorn.co.uk> - 2018-08-10 22:40 +0200
    Re: What time is it, really? Gene Heskett <gheskett@shentel.net> - 2018-08-09 17:10 +0200
    Re: What time is it, really? Darac Marjal <mailinglist@darac.org.uk> - 2018-08-09 17:20 +0200
      Re: What time is it, really? Greg Wooledge <wooledg@eeg.ccf.org> - 2018-08-09 18:00 +0200
        Re: What time is it, really? Andre Majorel <aym-naibed@teaser.fr> - 2018-08-09 19:10 +0200
        Re: What time is it, really? Nicolas George <george@nsup.org> - 2018-08-09 19:20 +0200
        Re: What time is it, really? Michael Stone <mstone@debian.org> - 2018-08-09 20:00 +0200
    Re: What time is it, really? deloptes <deloptes@gmail.com> - 2018-08-10 01:30 +0200
  Re: What time is it, really? Nicolas George <george@nsup.org> - 2018-08-09 16:50 +0200
    OT: What time is it, really? Martin <keine-eile@online.de> - 2018-08-09 17:10 +0200
      Re: OT: What time is it, really? Martin <keine-eile@online.de> - 2018-08-09 17:20 +0200
        Re: OT: What time is it, really? Nicolas George <george@nsup.org> - 2018-08-09 17:50 +0200
          Re: OT: What time is it, really? Martin <keine-eile@online.de> - 2018-08-09 18:10 +0200
        Re: OT: What time is it, really? Gene Heskett <gheskett@shentel.net> - 2018-08-09 18:20 +0200
          Re: OT: What time is it, really? Martin <keine-eile@online.de> - 2018-08-09 18:30 +0200
            Re: OT: What time is it, really? Gene Heskett <gheskett@shentel.net> - 2018-08-09 19:40 +0200
              Re: OT: What time is it, really? Anders Andersson <pipatron@gmail.com> - 2018-08-10 12:00 +0200
                Re: OT: What time is it, really? Gene Heskett <gheskett@shentel.net> - 2018-08-10 13:50 +0200
      Re: OT: What time is it, really? Nicolas George <george@nsup.org> - 2018-08-09 17:20 +0200
    Re: What time is it, really? Fred <fred@blakemfg.com> - 2018-08-09 18:50 +0200
      Re: What time is it, really? Nicolas George <george@nsup.org> - 2018-08-09 19:00 +0200
      Re: What time is it, really? Greg Wooledge <wooledg@eeg.ccf.org> - 2018-08-09 19:00 +0200
      Re: What time is it, really? Michael Stone <mstone@debian.org> - 2018-08-09 20:00 +0200
  Re: What time is it, really? Gene Heskett <gheskett@shentel.net> - 2018-08-09 16:50 +0200

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