[ntp:questions] Any samples for NTP/SNTP client code?
guuwwe at hotmail.com
guuwwe at hotmail.com
Mon Dec 3 18:11:11 UTC 2007
On Dec 3, 3:34 am, da... at ex.djwhome.demon.co.uk.invalid (David
Woolley) wrote:
> In article <17a3f3c2-3946-4fec-aaa0-6e18ee4e4... at n20g2000hsh.googlegroups.com>,
>
> guu... at hotmail.com wrote:
> > QueryPerformanceCounter() directly off the hardware. Windows
> > scheduling has no impact here, the drawbacks of tick counts do not
>
> Windows scheduling will cause uncertainty in the time you get from
> your SNTP requests which you use to calibrate the performance counters.
> (It will also cause uncertainties in the time of whatever real world
> event is associated with the times being recorded by your software.)
>
Windows scheduling will NOT cause any bigger uncertainty than many
other factors including network delays or scheduling on my Linksys
router
(probably Unix-like OS) that relays all my incoming/outgoing IP
traffic.
The most important thing is that my code will be able to measure
fairly
consistently the time between sending a request and receiving a
reply
for ***all*** servers in microseconds. I will use at least five
servers.
It would not be possible with TICKS but it is possible with high
frequency
counters because they operate on different principle as stated. This
is the
key difference!!! Consequently, it will be possible to estimate the
drift of the
PC counter and come up with servers' polling frequencies that
satisfy my
reqs for accuracy.
So do not make it more complicated than it is. The rest belongs to
the
algorithims I will use and you do not know them, and I am not ready
to
discusss them.
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