ConcurrentQueue 128-byte cache line

src/System.Collections.Concurrent/src/System/Collections/Concurrent/ConcurrentQueue.cs

@@ -1112,10 +1112,10 @@ internal struct Slot
 
     /// <summary>Padded head and tail indices, to avoid false sharing between producers and consumers.</summary>
     [DebuggerDisplay("Head = {Head}, Tail = {Tail}")]
-    [StructLayout(LayoutKind.Explicit, Size = 192)] // padding before/between/after fields based on typical cache line size of 64
+    [StructLayout(LayoutKind.Explicit, Size = 384)] // padding before/between/after fields based on worst case cache line size of 128
     internal struct PaddedHeadAndTail
     {
-        [FieldOffset(64)] public int Head;
-        [FieldOffset(128)] public int Tail;
+        [FieldOffset(128)] public int Head;
+        [FieldOffset(256)] public int Tail;
     }
 }

src/System.Collections.Concurrent/tests/Performance/ConcurrentQueuePerfTest.netcoreapp.cs

@@ -0,0 +1,44 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Xunit.Performance;
+using Xunit;
+
+namespace System.Collections.Concurrent.Tests
+{
+    public class Perf_ConcurrentQueueTests
+    {
+        /// <summary>
+        /// Creates a list containing a number of elements equal to the specified size
+        /// </summary>
+        [Benchmark]
+        [InlineData(8, 1000)]
+        [InlineData(50, 1000)]
+        public void Enqueue_Dequeue(int threadsCount, int itemsPerThread)
+        {
+            var q = new ConcurrentQueue<int>();
+            Task.WaitAll((from i in Enumerable.Range(0, threadsCount) select Task.Run(() =>
+            {
+                var random = new Random();
+                for (int j = 0; j < itemsPerThread; j++)
+                {
+                    switch (random.Next(2))
+                    {
+                        case 0:
+                            q.Enqueue(random.Next(int.MaxValue));
+                            break;
+                        case 1:
+                            int d;
+                            q.TryDequeue(out d);
+                            break;
+                    }
+                }
+            })).ToArray());
+        }
+    }
+}

src/System.Collections.Concurrent/tests/Performance/System.Collections.Concurrent.Performance.Tests.csproj

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
+  <PropertyGroup>
+    <IncludePerformanceTests>true</IncludePerformanceTests>
+    <ProjectGuid>{13A6510E-E11C-4329-BCDD-4DE561AB6CC0}</ProjectGuid>
+    <DisableTests Condition="'$(TargetGroup)' == 'uap' AND ('$(ArchGroup)' == 'arm' OR '$(ArchGroup)' == 'arm64')">true</DisableTests>
+  </PropertyGroup>
+  <!-- Default configurations to help VS understand the configurations -->
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' " />
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' " />
+  <ItemGroup Condition="'$(DisableTests)' != 'true'">
+    <Compile Include="ConcurrentQueuePerfTest.netcoreapp.cs" />
+    <Compile Include="$(CommonTestPath)\System\PerfUtils.cs">
+      <Link>Common\System\PerfUtils.cs</Link>
+    </Compile>
+  </ItemGroup>
+  <ItemGroup Condition="'$(DisableTests)' != 'true'">
+    <ProjectReference Include="$(CommonPath)\..\perf\PerfRunner\PerfRunner.csproj">
+      <Project>{69e46a6f-9966-45a5-8945-2559fe337827}</Project>
+      <Name>PerfRunner</Name>
+    </ProjectReference>
+  </ItemGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
+</Project>

src/System.Threading.Tasks.Dataflow/src/Internal/ProducerConsumerQueues.cs

@@ -551,7 +551,7 @@ static class PaddingHelpers
     }
 
     /// <summary>Padding structure used to minimize false sharing in SingleProducerSingleConsumerQueue{T}.</summary>
-    [StructLayout(LayoutKind.Explicit, Size = PaddingHelpers.CACHE_LINE_SIZE - sizeof(Int32))] // Based on common case of 64-byte cache lines
+    [StructLayout(LayoutKind.Explicit, Size = PaddingHelpers.CACHE_LINE_SIZE - sizeof(Int32))]
     struct PaddingFor32
     {
     }