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From: "bruno at clisp dot org" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug time/30200] time sometimes appears to go backwards
Date: Tue, 21 Mar 2023 15:29:51 +0000	[thread overview]
Message-ID: <bug-30200-131-uyt88Frb4p@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-30200-131@http.sourceware.org/bugzilla/>

https://sourceware.org/bugzilla/show_bug.cgi?id=30200

--- Comment #13 from Bruno Haible <bruno at clisp dot org> ---
(In reply to Adhemerval Zanella from comment #12)
> So this problem *always* existed

From "This problem always existed" you cannot imply "This problem never caused
trouble, otherwise it would have been reported".

In https://sourceware.org/pipermail/libc-alpha/2023-March/146219.html I
explain:

On a typical system, there are
  - hundreds of programs that call gettimeofday() or timespec_get(),
  - hundreds of programs that call time().
Each time a program calls gettimeofday() or timespec_get(), and then,
within 1 to 3 milliseconds, a program (the same or a different one)
calls time(), there is the potential for trouble because the time
appears to go backwards. This trouble can occur with probability
between 0.1% and 0.3%.

This is the kind of trouble that does occur, but that people don't report
because
- it occurs only 1 in 300 to 1000 times,
- it is nearly impossible to track down to glibc, since it will appear as an
interoperation bug between two different programs in the first place.

-- 
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  parent reply	other threads:[~2023-03-21 15:29 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-05 17:21 [Bug time/30200] New: " bruno at clisp dot org
2023-03-05 17:22 ` [Bug time/30200] " bruno at clisp dot org
2023-03-05 17:23 ` bruno at clisp dot org
2023-03-05 17:55 ` girish946 at gmail dot com
2023-03-05 18:28 ` schwab@linux-m68k.org
2023-03-05 18:58 ` schwab@linux-m68k.org
2023-03-05 19:04 ` bruno at clisp dot org
2023-03-06 12:15 ` adhemerval.zanella at linaro dot org
2023-03-06 12:25 ` fweimer at redhat dot com
2023-03-06 12:45 ` bruno at clisp dot org
2023-03-06 13:08 ` adhemerval.zanella at linaro dot org
2023-03-06 13:14 ` fweimer at redhat dot com
2023-03-19 23:43 ` eggert at cs dot ucla.edu
2023-03-21  4:18 ` sam at gentoo dot org
2023-03-21 15:06 ` adhemerval.zanella at linaro dot org
2023-03-21 15:29 ` bruno at clisp dot org [this message]
2023-03-21 16:02 ` adhemerval.zanella at linaro dot org
2023-03-21 20:00 ` bruno at clisp dot org
2023-03-21 20:03 ` adhemerval.zanella at linaro dot org
2023-03-21 20:25 ` fw at deneb dot enyo.de
2023-03-21 20:41 ` adhemerval.zanella at linaro dot org

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