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From: Padraig Brady <padraig@antefacto.com>
To: Andi Kleen <ak@suse.de>
Cc: Alex Larsson <alexl@redhat.com>,
	Ulrich Drepper <drepper@cygnus.com>,
	linux-kernel@vger.kernel.org
Subject: Re: Finegrained a/c/mtime was Re: Directory notification problem
Date: Fri, 05 Oct 2001 13:44:20 +0100	[thread overview]
Message-ID: <3BBDAB24.7000909@antefacto.com> (raw)
In-Reply-To: <m3r8slywp0.fsf@myware.mynet> <Pine.LNX.4.33.0110031111470.29619-100000@devserv.devel.redhat.com> <20011003232609.A11804@gruyere.muc.suse.de>

Andi Kleen wrote:

>On Wed, Oct 03, 2001 at 11:15:04AM -0400, Alex Larsson wrote:
>
>>Is a nanoseconds field the right choice though? In reality you might not 
>>have a nanosecond resolution timer, so you would miss changes that appear
>>on shorter timescale than the timer resolution. Wouldn't a generation 
>>counter, increased when ctime was updated, be a better solution?
>>
>
>Near any CPU has a cycle counter builtin now, which gives you ns like
>resolution. In theory you could still get collisions on MP systems, 
>but window is small enough that it can be ignored in practice.
>
>-Andi
>
But the point is you, only ever would want nano second resolution to make
sure you notice all changes to a file. A more general (and much simpler)
solution would be to gen_count++ every time a file's modified. What other
applications would require better than second resolution on files?

Padraig.


  reply	other threads:[~2001-10-05 12:50 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Pine.LNX.4.33.0110022206100.29931-100000@devserv.devel.redhat.com.suse.lists.linux.kernel>
2001-10-03  7:53 ` Finegrained a/c/mtime was Re: Directory notification problem Andi Kleen
2001-10-03  8:06   ` Ulrich Drepper
2001-10-03 13:35     ` Eric W. Biederman
2001-10-03 14:11       ` Netfilter problem Kirill Ratkin
2001-10-03 21:42         ` Luigi Genoni
2001-10-03 15:24       ` Finegrained a/c/mtime was Re: Directory notification problem Gerhard Mack
2001-10-16 18:56         ` Riley Williams
2001-10-03 15:15     ` Alex Larsson
2001-10-03 21:26       ` Andi Kleen
2001-10-05 12:44         ` Padraig Brady [this message]
2001-10-05 12:59           ` Andrew Pimlott
2001-10-05 13:01           ` Andi Kleen
2001-10-05 13:15             ` Padraig Brady
2001-10-05 14:38               ` Andi Kleen
2001-10-05 15:00                 ` Padraig Brady
2001-10-05 19:12                   ` Andi Kleen
2001-10-08  8:39                     ` Padraig Brady
2001-10-08  8:58                       ` Padraig Brady
2001-10-08 10:04                       ` Trond Myklebust
2001-10-05 20:22                 ` Bernd Eckenfels
2001-10-03 17:45   ` Bernd Eckenfels
2001-10-13 15:24     ` Jamie Lokier
2001-10-13 16:12       ` Andi Kleen
2001-10-13 19:38         ` Jamie Lokier

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