benchmark-localfunctions-vs-lambdas's Introduction

Benchmark LocalFunctions vs Lambdas

Benchmark the statements in the following article https://docs.microsoft.com/en-us/dotnet/csharp/local-functions-vs-lambdas

 public static int LambdaFactorial(int n)
        {
            Func<int, int> nthFactorial = default(Func<int, int>);
            nthFactorial = (number) => (number < 2) ?
                1 : number * nthFactorial(number - 1);
            return nthFactorial(n);
        }

   public static int LocalFunctionFactorial(int n)
        {
            return nthFactorial(n);
            int nthFactorial(int number) => (number < 2) ?
                1 : number * nthFactorial(number - 1);
        }

Results

BenchmarkDotNet=v0.10.6, OS=Windows 10 Redstone 1 (10.0.14393)
Processor=Intel Core i5-4590 CPU 3.30GHz (Haswell), ProcessorCount=4
Frequency=3215225 Hz, Resolution=311.0202 ns, Timer=TSC
  [Host]     : Clr 4.0.30319.42000, 32bit LegacyJIT-v4.7.2053.0
  DefaultJob : Clr 4.0.30319.42000, 32bit LegacyJIT-v4.7.2053.0

Method	N	Mean	Error	StdDev	Min	Max	Gen 0	Allocated
LambdaFactorial	3	14.707 ns	0.1897 ns	0.1775 ns	14.443 ns	15.023 ns	0.0140	44 B
LocalFunctionFactorial	3	4.111 ns	0.0469 ns	0.0439 ns	4.057 ns	4.196 ns	-	0 B
LambdaFactorial	10	31.992 ns	0.0707 ns	0.0591 ns	31.917 ns	32.090 ns	0.0139	44 B
LocalFunctionFactorial	10	15.327 ns	0.0622 ns	0.0582 ns	15.230 ns	15.424 ns	-	0 B
LambdaFactorial	20	62.756 ns	0.0966 ns	0.0698 ns	62.631 ns	62.878 ns	0.0139	44 B
LocalFunctionFactorial	20	37.762 ns	0.2754 ns	0.2576 ns	37.210 ns	38.106 ns	-	0 B