Messages in this thread | | | Date | Tue, 28 Mar 2006 00:30:27 +0200 | From | Eric Piel <> | Subject | Re: uptime increases during suspend |
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27.03.2006 21:53, Peter T. Breuer wrote/a écrit: > 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. It seems that what you are really looking for in your application is a monotonic clock. Linux has such thing since few releases. Using CLOCK_MONOTONIC (cf "man 3 clock_gettime") may look much less hacky than using the uptime ;-)
Now... concerning the suspend effect on this clock, I don't know. It's probably the same problem as uptime: no official semantic has ever been stated yet... Does anyone know?
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