[ntp:questions] Re: How application get precise time from Win NT/XP system time that synchronies to NTP

Roger Chou rgr.chou at gmail.com
Wed Mar 30 16:00:08 UTC 2005

"Martin Burnicki" <martin.burnicki at meinberg.de> ???
news:7nlqh2-vtb.ln1 at gateway.py.meinberg.de ???...
> Roger,
> Roger Chou ??? wrote:
> > Martin,
> >
> > If my application polls the system time once every tick, i.e. 10
> > millisecond, can I get nanosecond resolution and accuracy that NTP can
> > provide?
> As Terje already mentioned in his reply, the problem is in the Windows
> implementation. Since the code is in the HAL, and the HAL is different for
> uniprocessor machines and multiprocessor machines, the program behaves
> differently if running on DMP or non-SMP machines.
> If you try to interpolate using a timer callback function, that function
> be called immediately after a timer tick, or just a few milliseconds
> if another application uses the multimedia timers as described in my
> original post. Unfortunately I've found that there's still a jitter of 1
> millisecond in the callback rate while the multimedia timers are active.
> Martin
> -- 
> Martin Burnicki
> Meinberg Funkuhren
> Bad Pyrmont
> Germany


I would like to try polls Windows 2000/ XP system time. Can you tell me how
to do it? Only poll once every tick, see if I can get 1ms resolution?


Roger Chou

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