What is the equivalent to System.nanoTime() in .NET?

Question

The title is pretty much self-explanatory, I'm killing myself over this simplicity.

Looked here, but it isn't much helpful.

Schapira

Answer 1

I think that the Stopwatch class is what you are looking for.

Mesarch

+1, For timing (vs. getting the absolute time), Stopwatch is it. – Andante

Stopwatch is definitely the best way to time things in the BCL, it's just not accurate to nanoseconds. – Lueck

@overstood: Yes, the accuracy is not down to nanoseconds, just like the nanoTime method. :) – Mesarch

Answer 2

If you want a timestamp to be compared between different processes, different languages (Java, C, C#), under GNU/Linux and Windows (Seven at least):

Java:

java.lang.System.nanoTime();

C GNU/Linux:

static int64_t hpms_nano() {
   struct timespec t;
   clock_gettime( CLOCK_MONOTONIC, &t );
   int64_t nano = t.tv_sec;
   nano *= 1000;
   nano *= 1000;
   nano *= 1000;
   nano += t.tv_nsec;
   return nano;
}

C Windows:

static int64_t hpms_nano() {
   static LARGE_INTEGER ticksPerSecond;
   if( ticksPerSecond.QuadPart == 0 ) {
      QueryPerformanceFrequency( &ticksPerSecond );
   }
   LARGE_INTEGER ticks;
   QueryPerformanceCounter( &ticks );
   uint64_t nano = ( 1000*1000*10UL * ticks.QuadPart ) / ticksPerSecond.QuadPart;
   nano *= 100UL;
   return nano;
}

C#:

private static long nanoTime() {
   long nano = 10000L * Stopwatch.GetTimestamp();
   nano /= TimeSpan.TicksPerMillisecond;
   nano *= 100L;
   return nano;
}

Headstall

Answer 3

DateTime.Now will give you the current time in milliseconds, but time that is accurate to nanoseconds is fairly impractical, at least in Windows.

Seaway

I believe the accuracy of DateTime.Now is ~15 or 20 milliseconds. It has more precision than accuracy. – Scrim

Answer 4

the closest thing that i could find is the DateTime.ToFileTime() method. you can call this on an instance of a DateTime like so:

long starttime = DateTime.Now.ToFileTime()

The method returns a Windows File Time:

A Windows file time is a 64-bit value that represents the number of 100-nanosecond intervals that have elapsed since 12:00 midnight, January 1, 1601 A.D. (C.E.) Coordinated Universal Time (UTC).

you could at least time down to 100 ns intervals with it.

src: http://msdn.microsoft.com/en-us/library/system.datetime.tofiletime.aspx

Wheedle

This only gives you 100 ns accuracy for the time of the last windows timer update, which happens every 15 to 16 ms – Lueck

Answer 5

DateTime.Now.Ticks

I was trying to find the answer to this to run some performance testing.

DateTime startTime = DateTime.Now;
generatorEntity.PopulateValueList();
TimeSpan elapsedTime = DateTime.Now - startTime;
Console.WriteLine("Completed! time(ticks) - " + elapsedTime.Ticks);

Whimper

Answer 6

I think you're going to hit the hard limits of the OS if you're timing in nanoseconds. Here's a good article on the topic:

http://www.lochan.org/2005/keith-cl/useful/win32time.html

While Windows will happily return 100 nanosecond accuracy, the clock is only guaranteed to update once every 15.6 milliseconds or so. So effectively Windows returns the time at which those updates occurred to 100 nanosecond accuracy. For more accuracy than this you probably need to be prepared to write C or assembler and run and embedded OS.

Lueck

Answer 7

http://msdn.microsoft.com/de-de/library/system.datetime.ticks.aspx

somelike: DateTime.Ticks

Stanwinn