LambdaAllocTest.cs

// Copyright (c) ppy Pty Ltd <[email protected]>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.

using System;
using System.Runtime.CompilerServices;
using BenchmarkDotNet.Attributes;

namespace BenchmarksProject
{
    [MemoryDiagnoser]
    public class LambdaAllocTest
    {
        [Benchmark]
        public void TestInstanceMethodLambdaCapture()
        {
            for (int i = 0; i < 1000; i++)
                method1(() => method2());
        }

        [Benchmark]
        public void TestInstanceMethodDirectCapture()
        {
            for (int i = 0; i < 1000; i++)
                method1(method2);
        }

        [Benchmark]
        public void TestStaticMethodLambdaCapture()
        {
            for (int i = 0; i < 1000; i++)
                method1(() => staticMethod2());
        }

        [Benchmark]
        public void TestStaticMethodDirectCapture()
        {
            for (int i = 0; i < 1000; i++)
                method1(staticMethod2);
        }

        [Benchmark]
        public void TestLocalNonCapturingMethodLambdaCapture()
        {
            void localMethod2()
            {
            }

            for (int i = 0; i < 1000; i++)
                method1(() => localMethod2());
        }

        [Benchmark]
        public void TestLocalNonCapturingMethodDirectCapture()
        {
            void localMethod2()
            {
            }

            for (int i = 0; i < 1000; i++)
                method1(localMethod2);
        }

        [Benchmark]
        public void TestLocalNonCapturingStaticMethodLambdaCapture()
        {
            static void localMethod2()
            {
            }

            for (int i = 0; i < 1000; i++)
                method1(() => localMethod2());
        }

        [Benchmark]
        public void TestLocalNonCapturingStaticMethodDirectCapture()
        {
            static void localMethod2()
            {
            }

            for (int i = 0; i < 1000; i++)
                method1(localMethod2);
        }

        [Benchmark]
        public void TestLocalCapturingMethodLambdaCapture()
        {
            int x = 0;
            void method2() => x++;

            for (int i = 0; i < 1000; i++)
                method1(() => method2());
        }

        [Benchmark]
        public void TestLocalCapturingMethodDirectCapture()
        {
            int x = 0;
            void method2() => x++;

            for (int i = 0; i < 1000; i++)
                method1(method2);
        }

        [MethodImpl(MethodImplOptions.NoInlining)]
        private void method1(Action action)
        {
        }

        [MethodImpl(MethodImplOptions.NoInlining)]
        private void method2()
        {
        }

        [MethodImpl(MethodImplOptions.NoInlining)]
        private static void staticMethod2()
        {
        }
    }
}

Method	Mean	Error	StdDev	Gen 0	Gen 1	Gen 2	Allocated
TestInstanceMethodLambdaCapture	12.098 us	0.1361 us	0.1273 us	0.7629	-	-	64000 B
TestInstanceMethodDirectCapture	11.360 us	0.0398 us	0.0352 us	0.7629	-	-	64000 B
TestStaticMethodLambdaCapture	2.173 us	0.0013 us	0.0012 us	-	-	-	-
TestStaticMethodDirectCapture	12.028 us	0.2275 us	0.2708 us	0.7629	-	-	64000 B
TestLocalNonCapturingMethodLambdaCapture	2.179 us	0.0059 us	0.0052 us	-	-	-	-
TestLocalNonCapturingMethodDirectCapture	11.646 us	0.1288 us	0.1205 us	0.7629	-	-	64000 B
TestLocalNonCapturingStaticMethodLambdaCapture	2.176 us	0.0019 us	0.0015 us	-	-	-	-
TestLocalNonCapturingStaticMethodDirectCapture	12.156 us	0.2376 us	0.2222 us	0.7629	-	-	64000 B
TestLocalCapturingMethodLambdaCapture	2.201 us	0.0137 us	0.0114 us	-	-	-	96 B
TestLocalCapturingMethodDirectCapture	11.731 us	0.1157 us	0.0966 us	0.7629	-	-	64024 B