What is the equivalent to System.nanoTime() in .NE

问题:

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

Looked here, but it isn't much helpful.

回答1:

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

回答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;
}

回答3:

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

somelike: DateTime.Ticks

回答4:

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

回答5:

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

回答6:

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);

回答7:

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.