Richard B. Gilbert wrote: > Also note that Windows is a difficult environment! The clock ticks at > something like 17 millisecond intervals. If you really need/want time
Recent versions of ntpd force multi-media timers on, which reduces the interval between ticks, at the cost of an increased risk in lost ticks. Supposedly this was done because of having different measurement errors when they were on rather than off, and therefore having timing dependent on what application was running, but it also increases the accuracy. The real problem, though, is that Windows does not interpolate between ticks in the kernel. ntpd atttempts to do so in user space, but is rather vulnerable to scheduling delays, if the system is loaded, but ordinary applications will only see the time changing on a clock tick, not at about every microsecond, for older PC based Unix and Linux or every TSC tick for recent ones, particularly Linux. > to the nearest microsecond, Windows is a poor choice of O/S. There is > some way to interpolate between ticks which has been mentioned here from > time to time but I don't recall what it is. I have no need for time to > the nearest microsecond on my Windows systems and have not tried to > memorize the details! Yes. Generally, if you care about timing to an accuracy of more than a few tens of milliseconds, you should not be using Windows. Windows is optimised for human interfaces, so the most extreme timing it is designed for is probably that associated with playing simple MIDI files. _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
