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From: "James H. Cloos Jr." <cloos@jhcloos.com>
To: linux-kernel@vger.kernel.org
Cc: Jamie Lokier <jamie@shareable.org>, Paul Eggert <eggert@gnu.org>,
	Andi Kleen <ak@suse.de>,
	gcc@gcc.gnu.org, bug-coreutils@gnu.org
Subject: Re: Linux 2.6 nanosecond time stamp weirdness breaks GCC build
Date: Fri, 02 Apr 2004 02:57:41 -0500	[thread overview]
Message-ID: <m3isgi4xsa.fsf@lugabout.jhcloos.org> (raw)
In-Reply-To: <20040402011411.GE28520@mail.shareable.org> (Jamie Lokier's message of "Fri, 2 Apr 2004 02:14:11 +0100")

>>>>> "Jamie" == Jamie Lokier <jamie@shareable.org> writes:

Jamie> When re-reading an inode, rounding the time up is done by
Jamie> setting the tv_nsec field to 999999999.

Jamie> If the on-disk timestamp is "now", i.e. the current second if
Jamie> it's a 1-second resolution, then we can avoid setting the
Jamie> timestamp to a future time by setting the tv_nsec field to the
Jamie> current wall time's nanosecond value.  There is no need to
Jamie> round the time up any more than that.

Given how much time it will take to compare the file's timestamp to
current before choosing 999999999 or now for the tv_nsec field, is
it a reasonable shortcut to just always use now's nsec value?

Obviously it is not *that* many cycles to do the compare, but we are
talking about a nanoseconds field, and the current tv_sec could
increment during the compare....

-JimC


  reply	other threads:[~2004-04-02  7:58 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-04-01 19:28 Linux 2.6 nanosecond time stamp weirdness breaks GCC build Ulrich Weigand
2004-04-01 20:09 ` Andi Kleen
2004-04-01 20:39   ` Daniel Jacobowitz
2004-04-01 20:46     ` Andi Kleen
2004-04-01 21:01       ` Ulrich Weigand
2004-04-01 21:44         ` Andi Kleen
2004-04-01 22:39     ` Joe Buck
2004-04-01 22:44       ` Paul Jarc
2004-04-01 22:48       ` Ulrich Weigand
2004-04-01 23:58         ` Joe Buck
2004-04-02  0:13           ` Daniel Jacobowitz
2004-04-02  0:02   ` Jamie Lokier
2004-04-02  0:35   ` Paul Eggert
2004-04-02  1:14     ` Jamie Lokier
2004-04-02  7:57       ` James H. Cloos Jr. [this message]
2004-04-02  9:22       ` Paul Eggert
2004-04-02 16:23         ` Jamie Lokier
2004-04-02 20:45           ` Paul Eggert
2004-04-02 21:07             ` Jamie Lokier
2004-04-02 21:56               ` Paul Eggert
2004-04-03  4:59       ` Andrew Pimlott
2004-04-02  0:37   ` Andrew Morton
2004-06-07 16:03     ` Jörn Engel
2004-04-01 21:13 ` Janis Johnson
2004-04-01 21:41   ` Ulrich Weigand
2004-04-02  0:30   ` Alan Modra
2004-04-02  9:05 ` P
2004-04-02 17:27 ` Alexandre Oliva
  -- strict thread matches above, loose matches on Subject: below --
2004-04-01 20:51 Michael Elizabeth Chastain

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