Groups > comp.lang.java.programmer > #37469

Is time an illusion?

From	Daniele Futtorovic <da.futt.news@laposte.net>
Newsgroups	comp.lang.java.programmer
Subject	Is time an illusion?
Date	2017-09-25 22:30 +0200
Organization	A noiseless patient Spider
Message-ID	<oqbp1u$947$1@dont-email.me> (permalink)

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Cheers,

I'm trying to synchronise a process between two machines (actual, not
virtual). I require sub-millisecond precision.

I initialise clocks backed by System#nanoTime() on each end and
synchronise them somehow (there'll be some deviation at this point.
Doesn't matter). Subsequently, I time my process on each end relative to
this starting point.

I have the impression that I'm seeing time drift in this process.
Disregarding measurement errors, the differences between the clocks seem
to increase over time.

Q: Is this to be expected? I've been trying to read up on it a bit
(Oracle memory-holing all the sun.com blogs doesn't help), but wanted
some confirmation: is time really an illusion? Are 10^9 nanoseconds on
box A possibly not 10^9 nanoseconds on box B?

If so, seriously, what the heck? I'm aware I might have stumbled on a
very elementary truth here after so many years in the business, but I
must say, the idea itself feels deeply unsettling.

Existential musings aside, would any of you have suggestions as to how
tackle the issue?

-- 
DF.

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Thread

Is time an illusion? Daniele Futtorovic <da.futt.news@laposte.net> - 2017-09-25 22:30 +0200
  Re: Is time an illusion? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-09-25 18:02 -0400
    Re: Is time an illusion? Daniele Futtorovic <da.futt.news@laposte.net> - 2017-09-26 00:16 +0200
      Re: Is time an illusion? Jerry Stuckle <jstucklex@attglobal.net> - 2017-09-25 19:18 -0400
      Re: Is time an illusion? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-09-26 15:37 -0400
        Re: Is time an illusion? Daniele Futtorovic <da.futt.news@laposte.net> - 2017-09-27 01:13 +0200
          Re: Is time an illusion? Jerry Stuckle <jstucklex@attglobal.net> - 2017-09-26 21:00 -0400
            Re: Is time an illusion? Daniele Futtorovic <da.futt.news@laposte.net> - 2017-09-27 04:26 +0200
              Re: Is time an illusion? Jerry Stuckle <jstucklex@attglobal.net> - 2017-09-26 23:32 -0400
                Re: Is time an illusion? Daniele Futtorovic <da.futt.news@laposte.net> - 2017-09-28 10:58 +0200
                Re: Is time an illusion? Jerry Stuckle <jstucklex@attglobal.net> - 2017-09-28 12:50 -0400
            Re: Is time an illusion? Eric Douglas <e.d.programmer@gmail.com> - 2017-09-27 05:25 -0700
            Re: Is time an illusion? Arne Vajhøj <arne@vajhoej.dk> - 2017-09-30 22:57 -0400
  Re: Is time an illusion? Arne Vajhøj <arne@vajhoej.dk> - 2017-09-25 20:22 -0400
  Re: Is time an illusion? Marcel Mueller <news.5.maazl@spamgourmet.org> - 2017-09-26 20:18 +0200
    Re: Is time an illusion? Daniele Futtorovic <da.futt.news@laposte.net> - 2017-09-27 01:30 +0200
      Re: Is time an illusion? lewbloch@gmail.com - 2017-09-28 10:52 -0700
  Re: Is time an illusion? Eric Douglas <e.d.programmer@gmail.com> - 2017-09-26 12:59 -0700
    Re: Is time an illusion? Daniele Futtorovic <da.futt.news@laposte.net> - 2017-09-27 01:42 +0200
  Re: Is time an illusion? lewbloch@gmail.com - 2017-09-28 10:49 -0700
    Re: Is time an illusion? Robert Klemme <shortcutter@googlemail.com> - 2017-09-28 22:33 +0200

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