Benchmark-Results.md

BenchmarkDotNet=v0.12.0, OS=Windows 10.0.18363
Intel Core i5-4430 CPU 3.00GHz (Haswell), 1 CPU, 4 logical and 4 physical cores
.NET Core SDK=3.1.200
  [Host]     : .NET Core 3.1.2 (CoreCLR 4.700.20.6602, CoreFX 4.700.20.6702), X64 RyuJIT DEBUG
  DefaultJob : .NET Core 3.1.2 (CoreCLR 4.700.20.6602, CoreFX 4.700.20.6702), X64 RyuJIT

Method	Mean	Error	StdDev	Ratio	Gen 0	Gen 1	Gen 2	Allocated
ConsoleWriteLine	3.263 ns	0.0060 ns	0.0053 ns	1.00	-	-	-	-
LogInfo	1.943 ns	0.0273 ns	0.0255 ns	0.59	-	-	-	-

Benchmarks.fs

module DemoFs.Benchmarks

open BenchmarkDotNet.Attributes
open System.IO
open System.Runtime.CompilerServices

[<Interface>]
type ILogger = 
    abstract Info: string -> unit
    
[<Interface>]
type ILog =
    abstract Logger: ILogger
    
[<Sealed>]
type LiveLogger() =
    [<MethodImpl(MethodImplOptions.AggressiveInlining)>]
    member _.Info (fmt: string) = TextWriter.Null.WriteLine(fmt)
    interface ILogger with member this.Info fmt = this.Info fmt
    
module Log =
    let live = LiveLogger()
    
    [<MethodImpl(MethodImplOptions.AggressiveInlining)>]
    let info (env: #ILog) msg = env.Logger.Info msg
    
[<Struct;NoEquality;NoComparison>]
type AppEnv =
    member inline _.Logger : ILogger = upcast Log.live
    interface ILog with
        member this.Logger = this.Logger

[<MemoryDiagnoser>]
type EnvBenchmark() =
    
    static let message = "hello world"
    
    [<Benchmark(Baseline=true)>]
    member _.ConsoleWriteLine() = TextWriter.Null.WriteLine(message)

    [<Benchmark>]
    member _.LogInfo() = Log.info (AppEnv()) message

Program.fs

open System
open System.Reflection
open System.Threading
open BenchmarkDotNet.Running

[<EntryPoint>]
let main argv =
    BenchmarkSwitcher.FromAssembly(Assembly.GetExecutingAssembly()).Run(argv) |> ignore