Added Dispatcher Benchmarks (akkadotnet#6140)

* added parameterized Dispatcher benchmarks

* fixed naming - also, pull all config from Akka defaults

src/benchmark/Akka.Benchmarks/Dispatch/DispatcherBenchmarks.cs

@@ -0,0 +1,121 @@
+// //-----------------------------------------------------------------------
+// // <copyright file="DispatcherBenchmarks.cs" company="Akka.NET Project">
+// //     Copyright (C) 2009-2022 Lightbend Inc. <http://www.lightbend.com>
+// //     Copyright (C) 2013-2022 .NET Foundation <https://github.com/akkadotnet/akka.net>
+// // </copyright>
+// //-----------------------------------------------------------------------
+
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Akka.Actor;
+using Akka.Benchmarks.Configurations;
+using Akka.Configuration;
+using Akka.Dispatch;
+using BenchmarkDotNet.Attributes;
+using IRunnable = Akka.Dispatch.IRunnable;
+
+namespace Akka.Benchmarks.Dispatch
+{
+    /// <summary>
+    /// Used to test the performance of various dispatchers
+    /// </summary>
+    [Config(typeof(MicroBenchmarkConfig))]
+    public class DispatcherBenchmarks
+    {
+        private ActorSystem _sys;
+        private DefaultDispatcherPrerequisites _prereqs;
+
+        private MessageDispatcher _dispatcher;
+
+        [Params(1_000_000)] // higher values will cause the CallingThreadDispatcher to stack overflow
+        public int TaskCount { get; set; }
+
+        [ParamsSource(nameof(AllConfigurators))]
+        public DispatcherConfig Configurator { get; set; }
+
+        public class DispatcherConfig
+        {
+            public DispatcherConfig(Config config, string name)
+            {
+                Config = config;
+                Name = name;
+            }
+
+            public Config Config { get; }
+
+            public string Name { get; }
+
+            public override string ToString()
+            {
+                return Name;
+            }
+        }
+
+        private static readonly Config DefaultConfig = Akka.Remote.Configuration.RemoteConfigFactory.Default()
+            .WithFallback(Akka.Configuration.ConfigurationFactory.Default());
+
+        public IEnumerable<DispatcherConfig> AllConfigurators()
+        {
+            yield return new DispatcherConfig(DefaultConfig.GetConfig("akka.actor.default-dispatcher"), "DefaultThreadPool");
+            yield return new DispatcherConfig(DefaultConfig.GetConfig("akka.actor.internal-dispatcher"), "ForkJoin(sys)");
+            yield return new DispatcherConfig(DefaultConfig.GetConfig("akka.remote.default-remote-dispatcher"), "ForkJoin(remote)");
+            yield return new DispatcherConfig(@" executor = channel-executor
+                throughput=30", "ChannelD");
+            yield return new DispatcherConfig(@" executor = task-executor
+                throughput=30", "TaskD");
+        }
+
+        private TaskCompletionSource<int> _tcs;
+
+        public sealed class RunnableTarget : IRunnable
+        {
+            private readonly TaskCompletionSource<int> _tcs;
+            private readonly int _target;
+            private int _counter = 0;
+
+            public RunnableTarget(TaskCompletionSource<int> tcs, int target)
+            {
+                _tcs = tcs;
+                _target = target;
+            }
+
+            public void Run()
+            {
+                if (Interlocked.Increment(ref _counter) >= _target)
+                {
+                    _tcs.TrySetResult(_counter);
+                }
+            }
+        }
+
+        private RunnableTarget _runnable;
+
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            _sys = ActorSystem.Create("Bench");
+            _prereqs = new DefaultDispatcherPrerequisites(_sys.EventStream, _sys.Scheduler, _sys.Settings,
+                _sys.Mailboxes);
+            var configurator = new DispatcherConfigurator(Configurator.Config, _prereqs);
+            _dispatcher = configurator.Dispatcher();
+            _tcs = new TaskCompletionSource<int>();
+            _runnable = new RunnableTarget(_tcs, TaskCount);
+        }
+
+        [GlobalCleanup]
+        public void CleanUp()
+        {
+            _sys.Terminate().Wait();
+        }
+
+        [Benchmark]
+        public async Task RunDispatcher()
+        {
+            for (var i = 0; i < TaskCount; i++)
+                _dispatcher.Schedule(_runnable);
+            await _tcs.Task;
+        }
+    }
+}

src/benchmark/Akka.Benchmarks/Dispatch/MailboxThroughputBenchmarks.cs

@@ -69,6 +69,12 @@ public void Setup()
             _msg = new Envelope("hit", ActorRefs.NoSender);
         }
 
+        [GlobalCleanup]
+        public void CleanUp()
+        {
+            _system.Terminate().Wait();
+        }
+
         [IterationSetup]
         public void IterationSetup()
         {