From 12e80789cc87264bc4d98d4bb9a02c4141b7b70a Mon Sep 17 00:00:00 2001
From: Peter Sollich <petersol@microsoft.com>
Date: Wed, 18 May 2022 17:21:48 +0200
Subject: [PATCH] Add the repro case for github issue #68443
 (https://github.com/dotnet/runtime/issues/68443) as a GC test case.

---
 src/tests/GC/Stress/Tests/DictionaryGrowth.cs | 44 +++++++++++++++++++
 .../GC/Stress/Tests/DictionaryGrowth.csproj   | 10 +++++
 2 files changed, 54 insertions(+)
 create mode 100644 src/tests/GC/Stress/Tests/DictionaryGrowth.cs
 create mode 100644 src/tests/GC/Stress/Tests/DictionaryGrowth.csproj

diff --git a/src/tests/GC/Stress/Tests/DictionaryGrowth.cs b/src/tests/GC/Stress/Tests/DictionaryGrowth.cs
new file mode 100644
index 00000000000000..6e8338a7544319
--- /dev/null
+++ b/src/tests/GC/Stress/Tests/DictionaryGrowth.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.
+
+// This test causes a lot of ephemeral and background GCs to happen
+// It's a repro case for a race condition in background GC
+
+using System;
+using System.Collections.Generic;
+using System.Threading;
+
+internal class Program
+{
+    static void Run()
+    {
+        for (int iter = 0; iter < 1000_000; iter++)
+        {
+            var d = new Dictionary<string, ValueTuple<int, int>>();
+            for (int i = 0; i < 10 * 1000; i++)
+            {
+                d[i.ToString()] = new ValueTuple<int, int>(i, -1);
+            }
+        }
+    }
+
+    static void Main(string[] args)
+    {
+        int startTick = System.Environment.TickCount;
+        const int threadCount = 4;
+        Thread[] ta = new Thread[threadCount];
+        for (int i = 0; i < threadCount; i++)
+        {
+            ThreadStart ts = new ThreadStart(Run);
+            Thread t = new Thread(ts);
+            t.Start();
+            ta[i] = t;
+        }
+        for (int i = 0; i < threadCount; i++)
+        {
+            ta[i].Join();
+        }
+        double elapsed = 0.001*(System.Environment.TickCount - startTick);
+        Console.WriteLine("{0} seconds", elapsed);
+    }
+}
diff --git a/src/tests/GC/Stress/Tests/DictionaryGrowth.csproj b/src/tests/GC/Stress/Tests/DictionaryGrowth.csproj
new file mode 100644
index 00000000000000..1bd35237646c71
--- /dev/null
+++ b/src/tests/GC/Stress/Tests/DictionaryGrowth.csproj
@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <CLRTestKind>BuildOnly</CLRTestKind>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="DictionaryGrowth.cs" />
+  </ItemGroup>
+</Project>