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From: "Patrick J. LoPresti" <lopresti@gmail.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
	Andi Kleen <andi@firstfloor.org>,
	linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Proposal: Use hi-res clock for file timestamps
Date: Tue, 17 Aug 2010 12:34:58 -0700	[thread overview]
Message-ID: <AANLkTi=sOW0Cgci+xX6rRmz+B-is0xb8DoKD350bFJN1@mail.gmail.com> (raw)
In-Reply-To: <20100817203941.729830b7@lxorguk.ukuu.org.uk>

On Tue, Aug 17, 2010 at 12:39 PM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

>        if (time_now == time_last)
>                return { time_last , ++ct };
>        else {
>                ct = 0;
>                time_last = time_now
>                return { time_last , 0 };
>        }
>
> providing it is done with the same 'ct' across the fs and you can't do
> enough ops/second to wrap the nanosecs - which should be fine for now,
> your ordering is still safe is it not ?

Yes, that would work.   Assuming you use atomic counters, else there
is a risk of the visible time ticking backwards.  It seems like a lot
of effort just to avoid having accurate timestamps on your files,
though.

I am having trouble seeing why this is a better idea than a simple
mount option to obtain decent resolution timestamps.  (Not that we
can't have both...)  Is there any objection to the mount option I am
proposing?

For the Nth time, I am willing to produce and test the patch, but not
if there is zero chance of it being accepted.

 - Pat

  parent reply	other threads:[~2010-08-17 19:35 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-13 18:25 Proposal: Use hi-res clock for file timestamps Patrick J. LoPresti
2010-08-13 18:45 ` john stultz
2010-08-13 18:57   ` Patrick J. LoPresti
2010-08-13 19:09     ` john stultz
2010-08-13 20:53       ` Patrick J. LoPresti
2010-08-14 16:45         ` Patrick J. LoPresti
2010-08-15  1:50         ` Bret Towe
2010-08-13 19:57     ` Jim Rees
2010-08-13 20:26       ` john stultz
2010-08-13 20:52         ` Jim Rees
2010-08-17 14:54 ` Andi Kleen
2010-08-17 17:41   ` J. Bruce Fields
2010-08-17 18:29     ` Andi Kleen
2010-08-17 18:50       ` Patrick J. LoPresti
2010-08-17 19:04       ` J. Bruce Fields
2010-08-17 19:18         ` Patrick J. LoPresti
2010-08-17 19:39           ` Alan Cox
2010-08-17 19:29             ` J. Bruce Fields
2010-08-17 19:52               ` Alan Cox
2010-08-18  5:53               ` Neil Brown
2010-08-18 14:46                 ` Patrick J. LoPresti
2010-08-18 17:32                 ` J. Bruce Fields
2010-08-18 18:15                   ` Chuck Lever
2010-08-18 23:41                     ` Neil Brown
2010-08-19  0:52                       ` Neil Brown
2010-08-19  2:08                         ` J. Bruce Fields
2010-08-19  2:44                           ` Neil Brown
2010-08-19 22:46                             ` J. Bruce Fields
2010-08-18 23:47                   ` Neil Brown
2010-08-18 17:50                 ` Andi Kleen
2010-08-18 18:54                   ` J. Bruce Fields
2010-08-18 19:25                     ` Andi Kleen
2010-08-18 19:30                       ` J. Bruce Fields
2010-08-17 19:34             ` Patrick J. LoPresti [this message]
2010-08-17 19:54               ` Alan Cox
2010-08-17 19:43                 ` Patrick J. LoPresti
2010-08-17 19:45                   ` J. Bruce Fields
2010-08-18 18:12               ` J. Bruce Fields
2010-08-19  1:41                 ` john stultz
2010-08-19  2:31                   ` J. Bruce Fields
2010-08-19  3:17                     ` john stultz
2010-08-19 22:53                       ` J. Bruce Fields
2010-08-18 18:20       ` David Woodhouse
2010-08-18 18:32         ` Patrick J. LoPresti
2010-08-18 18:53         ` Andi Kleen

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