add AtomicCounterBenchmark

src/csharp/Grpc.Microbenchmarks/AtomicCounterBenchmark.cs

@@ -0,0 +1,52 @@
+#region Copyright notice and license
+
+// Copyright 2015 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#endregion
+
+using System;
+using System.Runtime.InteropServices;
+using BenchmarkDotNet.Attributes;
+using Grpc.Core.Internal;
+
+namespace Grpc.Microbenchmarks
+{
+    public class AtomicCounterBenchmark : CommonThreadedBase
+    {
+        protected override bool NeedsEnvironment => false;
+
+        // An example of testing scalability of a method that scales perfectly.
+        // This method provides a baseline for how well can CommonThreadedBase
+        // measure scalability.
+        const int Iterations = 20 * 1000 * 1000;  // High number to make the overhead of RunConcurrent negligible.
+        [Benchmark(OperationsPerInvoke = Iterations)]
+        
+        public void SharedAtomicCounterIncrement()
+        {
+            RunConcurrent(() => { RunBody(); });
+        }
+
+        readonly AtomicCounter sharedCounter = new AtomicCounter();
+
+        private int RunBody()
+        {
+            for (int i = 0; i < Iterations; i++)
+            {
+                sharedCounter.Increment();
+            }
+            return (int) sharedCounter.Count;
+        }
+    }
+}