[ntp:questions] Best solution for millisecond accuracy

Danny Mayer mayer at ntp.isc.org
Sun Mar 25 17:18:22 UTC 2007


David Woolley wrote:
> In article <46043069.1010200 at comcast.net>,
> Richard B. gilbert <rgilbert88 at comcast.net> wrote:
>> edouard funke wrote:
> 
>>> - change OS (again what is the impact ?)
>> Some operating systems keep time a little better than others.  Windows 
>> and Linux have both been known to lose clock interrupts during periods 
>> of high disk usage.  I've had good results with Solaris (8, 9, & 10) but 
>> others here seem to have had results differing from mine!
> 
> Also, Windows, in default configuration, will only provide a resolution
> of about 15 to 20ms (whatever the clock interrupt rate is) in the times
> provided to application programs.  ntpd plays tricks to make its own times
> more accurate, and therefore the phase of the system clock more accurate,
> but, in my experience, that breaks down when the system is heavily loaded.
> 
> It is possible that enabling multimedia timers will improve the resolution
> of time supplied to application programs; I haven't tested this.

The Windows implementation uses the multimedia timers to provide the
greatest accuracy.

Danny



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