It really is a feature of the history of the PC. The original IBM-PC used a chip called the Real Time Clock which was battery backed up (Do you remember needing to change the batteries on these ?) These operated when the machine was powered off and kept the time. The frequency of these was … Read more
You can see from the source that datetime objects don’t support anything more fine than microseconds. As pointed out by Mike Pennington in the comments, this is likely because computer hardware clocks aren’t nearly that precise. Wikipedia says that HPET has frequency “at least 10 MHz,” which means one tick per 100 nanoseconds. If you … Read more
Achieve microsecond accuracy in most browsers using: window.performance.now() See also: https://developer.mozilla.org/en-US/docs/Web/API/Performance.now() http://www.w3.org/TR/hr-time/ https://caniuse.com/high-resolution-time
I always use something like the following: public static String GetTimestamp(this DateTime value) { return value.ToString(“yyyyMMddHHmmssfff”); } This will give you a string like 200905211035131468, as the string goes from highest order bits of the timestamp to lowest order simple string sorting in your SQL queries can be used to order by date if you’re … Read more
Why would DateTime.Now be made less precise than what most CPU clocks could handle? A good clock should be both precise and accurate; those are different. As the old joke goes, a stopped clock is exactly accurate twice a day, a clock a minute slow is never accurate at any time. But the clock a … Read more
There is no ANSI C function that provides better than 1 second time resolution but the POSIX function gettimeofday provides microsecond resolution. The clock function only measures the amount of time that a process has spent executing and is not accurate on many systems. You can use this function like this: struct timeval tval_before, tval_after, … Read more
long milliseconds = DateTime.Now.Ticks / TimeSpan.TicksPerMillisecond; This is actually how the various Unix conversion methods are implemented in the DateTimeOffset class (.NET Framework 4.6+, .NET Standard 1.3+): long milliseconds = DateTimeOffset.Now.ToUnixTimeMilliseconds();
If you’re just looking for extremely precise measurements of elapsed time, use System.nanoTime(). System.currentTimeMillis() will give you the most accurate possible elapsed time in milliseconds since the epoch, but System.nanoTime() gives you a nanosecond-precise time, relative to some arbitrary point. From the Java Documentation: public static long nanoTime() Returns the current value of the most … Read more