Re: Question about /proc/uptime

[Rob Landley]

On 01/01/14 06:41, Martin Schwidefsky wrote:
> On Tue, 31 Dec 2013 22:17:39 -0600
> Rob Landley <rob@xxxxxxxxxxx> wrote:
>
> > On 12/30/13 09:26, Martin Schwidefsky wrote:
> > > On Mon, 30 Dec 2013 16:11:10 +0100
> > > Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
> > > > Not sure I understand... except that timekeeping_resume() does
> > > > __timekeeping_inject_sleeptime().
> > >
> > > Hmm, you are right. The sleeptime is added to the monotonic boottime.
> > > So the first value of /proc/uptime is the wall-time since boot.
> > > And the second value is combined idle time over all cpus.
> >
> > Is there an obvious way to query the non-suspend uptime from userspace?
>
> clock_gettime with CLOCK_MONOTONIC gives you the uptime minus without the
> suspend time.

Given that the clock_gettime man page says:

  CLOCK_MONOTONIC
    Clock that cannot be set and  represents  monotonic  time  since
    some unspecified starting point.

Can I rely on it _continuing_ to do so in future, and if so should the 
man page be clarified?

Rob
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