Good Practices

Use the Release build without an attached debugger

Never use the Debug build for benchmarking. Never. The debug version of the target method can run 10–100 times slower. The release mode means that you should have <Optimize>true</Optimize> in your csproj file or use /optimize for csc. Also your never should use an attached debugger (e.g. Visual Studio or WinDbg) during the benchmarking. The best way is build our benchmark in the Release mode and run it from the command line.

Try different environments

Please, don't extrapolate your results. Or do it very carefully. I remind you again: the results in different environments may vary significantly. If a Foo1 method is faster than a Foo2 method for CLR4, .NET Framework 4.5, x64, RyuJIT, Windows, it means that the Foo1 method is faster than the Foo2 method for CLR4, .NET Framework 4.5, x64, RyuJIT, Windows and nothing else. And you can not say anything about methods performance for CLR 2 or .NET Framework 4.6 or LegacyJIT-x64 or x86 or Linux+Mono until you try it.

Avoid dead code elimination

You should also use the result of calculation. For example, if you run the following code:

void Foo()
{
    Math.Exp(1);
}

then JIT can eliminate this code because the result of Math.Exp is not used. The better way is use it like this:

double Foo()
{
    return Math.Exp(1);
}

Power settings and other applications

  • Turn off all of the applications except the benchmark process and the standard OS processes. If you run benchmark and work in the Visual Studio at the same time, it can negatively affect to benchmark results.
  • If you use laptop for benchmarking, keep it plugged in and use the maximum performance mode.