Stopwatch for performance testing

Question

For some private project I use Stopwatch for performance measurement.

But on low repitition count of calls I want to measure, I end up with 0 ElapsedMilliseconds, which makes it difficult to calculate an average.

I thought about writing my own Stopwatch class. It could calculate with ticks and give a vague ElapsedMicroseconds based on Stopwatch.ElapsedTicks and TimeSpan.TicksPerMillisecond. This will probably be not a very good way.

I definitly need something that is backed up by the high performance counters of winapi, so datetime and such will not suffice.

Are there any other ideas?

Answer 1

If you got 0 ElapsedMicroseconds, that means that the interval is shorter than 1 ms. You may try measuring periods in Ticks and use Frequency:

  Stopwatch watch = Stopwatch.StartNew();
  ...
  // Estimated code here 
  ...
  watch.Stop();

  // Microseconds
  int microSeconds = (int)(watch.ElapsedTicks * 1.0e6 / Stopwatch.Frequency + 0.4999);
  // Nanoseconds (estimation)
  int nanoSeconds = (int)(watch.ElapsedTicks * 1.0e9 / Stopwatch.Frequency + 0.4999);

Answer 2

StopWatch is the thing you need. Use:

double diffMs = (stopWatch.ElapsedTicks * 1000.0) / Stopwatch.Frequency;

StopWathch.ElapsedMilliseconds is defined as long. Therefore it is not possible that it is more precise than one millisecond.