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ForNeVeR/FalseSharing.cs

Last active February 21, 2020 10:11
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False sharing test in C#.
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FalseSharing.cs
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;
namespace ConsoleApplication2
{
class Program
{
struct Fuck
{
public int x, y;
}
[StructLayout(LayoutKind.Explicit)]
struct Suck
{
[FieldOffset(0)]
public int x;
[FieldOffset(512)]
public int y;
}
private static Fuck fuck;
private static Suck suck;
static void Main(string[] args)
{
var t1 = new Thread(Thread1);
var t2 = new Thread(Thread2);
var t3 = new Thread(Thread3);
var t4 = new Thread(Thread4);
var timer = new Stopwatch();
timer.Start();
t1.Start();
t2.Start();
t1.Join();
t2.Join();
timer.Stop();
Console.WriteLine("False sharing: {0} ms", timer.ElapsedMilliseconds); // 617 ms
timer = new Stopwatch();
timer.Start();
t3.Start();
t4.Start();
t3.Join();
t4.Join();
timer.Stop();
Console.WriteLine("No false sharing: {0} ms", timer.ElapsedMilliseconds); // 393 ms
}
private static void Thread1()
{
for (int i = 0; i < 100000000; ++i)
{
++fuck.x;
}
}
private static void Thread2()
{
for (int i = 0; i < 100000000; ++i)
{
++fuck.y;
}
}
private static void Thread3()
{
for (int i = 0; i < 100000000; ++i)
{
++suck.x;
}
}
private static void Thread4()
{
for (int i = 0; i < 100000000; ++i)
{
++suck.y;
}
}
}
}
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