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in-reply-to: <200603271953.k2RJrTR28039@inv.it.uc3m.es>
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Subject: Re: uptime increases during suspend
Date: Mon, 27 Mar 2006 15:01:18 -0500
Message-ID: <Pine.LNX.4.61.0603271500050.16973@chaos.analogic.com>
Thread-Topic: uptime increases during suspend
Thread-Index: AcZR2Tb4DG4LU321Ttu3ioWvj7objA==
References: <200603271953.k2RJrTR28039@inv.it.uc3m.es>
From: "linux-os \(Dick Johnson\)" <linux-os@analogic.com>
To: "Peter T. Breuer" <ptb@inv.it.uc3m.es>
Cc: "john stultz" <johnstul@us.ibm.com>, <linux-kernel@vger.kernel.org>
Reply-To: "linux-os \(Dick Johnson\)" <linux-os@analogic.com>
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On Mon, 27 Mar 2006, Peter T. Breuer wrote:

> In article <1143484821.2168.16.camel@leatherman> you wrote:
>>> Would it be possible to get the old behaviour back?
>
>> Why exactly do you want this behavior? Maybe a better explanation would
>> help stir this discussion.
>
> I don't know why he wants it (uptime does not increase during
> hibernation) but I want it so that I can tell if I should time out or
> not on an alarm for inactivity in userspace!  The alarm should fire if
> there has been no activity for a while (30s) while activity is possible.
> If the machine is suspended, no activity is possible, so the alarm
> should not fire.
>
> This is to counteract sysadamins playing with system time (e.g. syncing
> with a net time server after bootup) which might cause artificial time
> outs. Causing a timeout has nasty consequences when, for example, your
> root fs is mounted over the net via daemons that do the network to-ing
> and fro-ing from userspace. The only way they have of getting an
> estimate of REAL time elapsed,  without admin playing about messing
> with them, is by surreptitiously snooping uptime, which more or less
> represents kernel jiffies.
>
> If you change uptime to not represente kernel jiffies, goodbye the last
> hope for counting CPU time passed from userspace. False timeouts WILL
> ensue, and root mounts will fail.
>
> Peter

Well uptime code can be modified to subtract the time (if any) in
hibernation. Then everybody is happy.


Cheers,
Dick Johnson
Penguin : Linux version 2.6.15.4 on an i686 machine (5589.42 BogoMips).
Warning : 98.36% of all statistics are fiction, book release in April.
_


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