From: Lars Marowsky-Bree <lmb@suse.de>
To: linux-kernel@vger.kernel.org
Subject: Re: Voyager subarchitecture for 2.5.46
Date: Sun, 10 Nov 2002 21:16:46 +0100 [thread overview]
Message-ID: <20021110201645.GI835@marowsky-bree.de> (raw)
In-Reply-To: <6usmy99osn.fsf@zork.zork.net>
On 2002-11-10T20:02:00,
Sean Neakums <sneakums@zork.net> said:
> > I believe you need it system-global. If task A tells task B "its
> > 10:30:00" and than task B does gettimeofday and gets "10:29:59", it
> > will be confused for sure.
> Hence the requirement that it be monotonically increasing.
Processes expecting time to increase strictly monotonically across process
boundaries will enjoy life in cluster settings or when the admin adjusts the
time.
In short, those programs are already broken.
Of course, physically that should be true, Star Trek or not ;), but it is a
really hard promise to keep across multiple nodes (think Mosix, CC/NC-NUMA or
even real clusters which distributed processing).
Serializing all gettimeofday() calls via a single counter at least is a rather
bad idea.
Sincerely,
Lars Marowsky-Brée <lmb@suse.de>
--
Principal Squirrel
SuSE Labs - Research & Development, SuSE Linux AG
"If anything can go wrong, it will." "Chance favors the prepared (mind)."
-- Capt. Edward A. Murphy -- Louis Pasteur
next prev parent reply other threads:[~2002-11-10 20:10 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-11-05 20:45 Voyager subarchitecture for 2.5.46 J.E.J. Bottomley
2002-11-06 2:31 ` john stultz
2002-11-06 13:43 ` Alan Cox
2002-11-06 21:35 ` john stultz
2002-11-06 15:03 ` J.E.J. Bottomley
2002-11-06 15:38 ` Alan Cox
2002-11-06 16:09 ` Christer Weinigel
2002-11-06 15:45 ` Linus Torvalds
2002-11-06 16:19 ` Alan Cox
2002-11-06 16:12 ` Linus Torvalds
2002-11-06 16:45 ` Alan Cox
2002-11-10 16:30 ` Pavel Machek
2002-11-10 18:59 ` Linus Torvalds
2002-11-10 19:18 ` Pavel Machek
2002-11-10 19:31 ` Linus Torvalds
2002-11-10 19:42 ` Pavel Machek
2002-11-10 19:48 ` Vojtech Pavlik
2002-11-10 20:02 ` Sean Neakums
2002-11-10 20:16 ` Lars Marowsky-Bree [this message]
2002-11-10 22:11 ` Alan Cox
2002-11-10 19:46 ` Vojtech Pavlik
2002-11-11 20:40 ` john stultz
2002-11-11 20:57 ` J.E.J. Bottomley
2002-11-11 21:36 ` William Lee Irwin III
2002-11-11 21:58 ` john stultz
2002-11-11 22:49 ` J.E.J. Bottomley
2002-11-11 23:12 ` john stultz
2002-11-12 12:16 ` Pavel Machek
2002-11-11 22:08 ` Vojtech Pavlik
2002-11-06 20:07 ` john stultz
2002-11-06 22:36 ` H. Peter Anvin
2002-11-06 19:30 ` john stultz
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