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From: John Stultz <john.stultz@linaro.org>
To: David Howells <dhowells@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: Apparent backward time travel in timestamps on file creation
Date: Thu, 30 Mar 2017 13:03:50 -0700	[thread overview]
Message-ID: <CALAqxLWR0g1dEOO0kMtpDL9grmKxTVx7ELhsW6055saQi+F1HA@mail.gmail.com> (raw)
In-Reply-To: <23410.1490902528@warthog.procyon.org.uk>

On Thu, Mar 30, 2017 at 12:35 PM, David Howells <dhowells@redhat.com> wrote:
> Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
>> The difference can be quite noticeable - basically the
>> "gettimeofday()" time will interpolate within timer ticks, while
>> "xtime" is just the truncated "time at timer tick" value _without_ the
>> correction.
>
> Is there any way to determine the error bar, do you know?  Or do I just make
> up a fudge factor?

Again, I'd utilize clock_gettime(CLOCK_REALTIME_COARSE, ...) for this
instead of playing with fudge factors.

thanks
-john

  parent reply	other threads:[~2017-03-30 20:03 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-30 17:30 Apparent backward time travel in timestamps on file creation David Howells
2017-03-30 18:07 ` Linus Torvalds
2017-03-30 18:49 ` John Stultz
2017-03-30 19:35 ` David Howells
2017-03-30 19:52   ` Linus Torvalds
2017-03-30 20:04     ` Linus Torvalds
2017-03-30 20:13     ` David Howells
2017-03-30 20:16       ` David Lang
2017-03-30 21:13       ` Linus Torvalds
2017-03-31 12:35         ` Bob Peterson
2017-03-30 22:22       ` David Howells
2017-03-30 20:03   ` John Stultz [this message]
2017-03-30 20:06     ` Linus Torvalds

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