[Olsr-users] 0.5.6 Routes disappear after 4 mins of uptime, then all OK - suspect clock sync

John Hay (spam-protected)
Wed Sep 3 06:12:25 CEST 2008


On Tue, Sep 02, 2008 at 11:29:01PM +0200, Bernd Petrovitsch wrote:
> On Die, 2008-09-02 at 21:16 +0200, John Hay wrote:
> > On Tue, Sep 02, 2008 at 07:24:01PM +0200, Bernd Petrovitsch wrote:
> > ...
> > > Not really:
> > > gettimeofday(2) and time(2) return the current date+time (read: that
> > > what the device thinks it is) or some representation of it.
> > > The problem with that is that it is not continuous because
> > > ntp/ntpdate/rdate/the admin/daylight-saving-time/... may change speed
> > > and value at any time (and I purposely ignore leap seconds).
> > > These values are great for syslog and other time values which refer to
> > > the rest of the planet.
> > > 
> > > For timeouts in select/poll/sleep/timers in general one wants a steady
> > > clock without jumps. And times(2) is the only portable sys-call I know
> > > of.
> > 
> > What about clock_gettime(2)? According to the FreeBSD man page it is
> 
> I assume you mean the CLOCK_MONOTONIC "version".
> Why not?

Yes.

> > part of IEEE Std 1003.1b-1993 (``POSIX.1'').
> 
> Sorry;-), but times(2) is also in SuSv3:
> http://www.opengroup.org/onlinepubs/009695399/functions/times.html

Well I was not clear. I did not mean that times(2) was not well
supported. Just that clock_gettime(2) might be widely available, if we
are looking for alternatives. It also does not work in ticks, which
might be useful or not depending on how one want to implement things.

John
-- 
John Hay -- (spam-protected) / (spam-protected)




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