added VectorClock benchmark (#4950)

* added VectorClock benchmark

* fixed broken benchmark comparisons

Author: Aaronontheweb

src/benchmark/Akka.Benchmarks/Cluster/VectorClockBenchmarks.cs

@@ -0,0 +1,157 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+using System.Text;
+using Akka.Benchmarks.Configurations;
+using Akka.Cluster;
+using BenchmarkDotNet.Attributes;
+using FluentAssertions;
+using static Akka.Cluster.VectorClock;
+
+namespace Akka.Benchmarks.Cluster
+{
+    [Config(typeof(MicroBenchmarkConfig))]
+    public class VectorClockBenchmarks
+    {
+        [Params(100, 500, 1000)]
+        public int ClockSize;
+
+        [Params(1000)]
+        public int Iterations;
+
+        internal (VectorClock clock, ImmutableSortedSet<VectorClock.Node> nodes) CreateVectorClockOfSize(int size)
+        {
+            return Enumerable.Range(1, size)
+                .Aggregate((VectorClock.Create(), ImmutableSortedSet<Node>.Empty),
+                    (tuple, i) =>
+                    {
+                        var (vc, nodes) = tuple;
+                        var node = Node.Create(i.ToString());
+                        return (vc.Increment(node), nodes.Add(node));
+                    });
+        }
+
+        internal VectorClock CopyVectorClock(VectorClock vc)
+        {
+            var versions = vc.Versions.Aggregate(ImmutableSortedDictionary<Node, long>.Empty,
+                (newVersions, pair) =>
+                {
+                    return newVersions.SetItem(Node.FromHash(pair.Key.ToString()), pair.Value);
+                });
+
+            return VectorClock.Create(versions);
+        }
+
+        private Node _firstNode;
+        private Node _lastNode;
+        private Node _middleNode;
+        private ImmutableSortedSet<Node> _nodes;
+        private VectorClock _vcBefore;
+        private VectorClock _vcBaseLast;
+        private VectorClock _vcAfterLast;
+        private VectorClock _vcConcurrentLast;
+        private VectorClock _vcBaseMiddle;
+        private VectorClock _vcAfterMiddle;
+        private VectorClock _vcConcurrentMiddle;
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            var (vcBefore, nodes) = CreateVectorClockOfSize(ClockSize);
+            _vcBefore = vcBefore;
+            _nodes = nodes;
+
+            _firstNode = nodes.First();
+            _lastNode = nodes.Last();
+            _middleNode = nodes[ClockSize / 2];
+
+            _vcBaseLast = vcBefore.Increment(_lastNode);
+            _vcAfterLast = _vcBaseLast.Increment(_firstNode);
+            _vcConcurrentLast = _vcBaseLast.Increment(_lastNode);
+            _vcBaseMiddle = _vcBefore.Increment(_middleNode);
+            _vcAfterMiddle = _vcBaseMiddle.Increment(_firstNode);
+            _vcConcurrentMiddle = _vcBaseMiddle.Increment(_middleNode);
+        }
+
+        private void CheckThunkFor(VectorClock vc1, VectorClock vc2, Action<VectorClock, VectorClock> thunk, int times)
+        {
+            var vcc1 = CopyVectorClock(vc1);
+            var vcc2 = CopyVectorClock(vc2);
+            for (var i = 0; i < times; i++)
+            {
+                thunk(vcc1, vcc2);
+            }
+        }
+
+        private void CompareTo(VectorClock vc1, VectorClock vc2, Ordering ordering)
+        {
+            vc1.CompareTo(vc2).Should().Be(ordering);
+        }
+
+        private void NotEqual(VectorClock vc1, VectorClock vc2)
+        {
+            (vc1 == vc2).Should().BeFalse();
+        }
+
+        [Benchmark]
+        public void VectorClock_comparisons_should_compare_same()
+        {
+            CheckThunkFor(_vcBaseLast, _vcBaseLast, (clock, vectorClock) => CompareTo(clock, vectorClock, Ordering.Same), Iterations);
+        }
+
+        [Benchmark]
+        public void VectorClock_comparisons_should_compare_Before_last()
+        {
+            CheckThunkFor(_vcBefore, _vcBaseLast, (clock, vectorClock) => CompareTo(clock, vectorClock, Ordering.Before), Iterations);
+        }
+
+        [Benchmark]
+        public void VectorClock_comparisons_should_compare_After_last()
+        {
+            CheckThunkFor(_vcAfterLast, _vcBaseLast, (clock, vectorClock) => CompareTo(clock, vectorClock, Ordering.After), Iterations);
+        }
+
+        [Benchmark]
+        public void VectorClock_comparisons_should_compare_Concurrent_last()
+        {
+            CheckThunkFor(_vcAfterLast, _vcConcurrentLast, (clock, vectorClock) => CompareTo(clock, vectorClock, Ordering.Concurrent), Iterations);
+        }
+
+        [Benchmark]
+        public void VectorClock_comparisons_should_compare_Before_middle()
+        {
+            CheckThunkFor(_vcBefore, _vcBaseMiddle, (clock, vectorClock) => CompareTo(clock, vectorClock, Ordering.Before), Iterations);
+        }
+
+        [Benchmark]
+        public void VectorClock_comparisons_should_compare_After_middle()
+        {
+            CheckThunkFor(_vcAfterMiddle, _vcBaseMiddle, (clock, vectorClock) => CompareTo(clock, vectorClock, Ordering.After), Iterations);
+        }
+
+        [Benchmark]
+        public void VectorClock_comparisons_should_compare_Concurrent_middle()
+        {
+            CheckThunkFor(_vcAfterMiddle, _vcConcurrentMiddle, (clock, vectorClock) => CompareTo(clock, vectorClock, Ordering.Concurrent), Iterations);
+        }
+
+        [Benchmark]
+        public void VectorClock_comparisons_should_compare_notEquals_Before_Middle()
+        {
+            CheckThunkFor(_vcBefore, _vcBaseMiddle, (clock, vectorClock) => NotEqual(clock, vectorClock), Iterations);
+        }
+
+        [Benchmark]
+        public void VectorClock_comparisons_should_compare_notEquals_After_Middle()
+        {
+            CheckThunkFor(_vcAfterMiddle, _vcBaseMiddle, (clock, vectorClock) => NotEqual(clock, vectorClock), Iterations);
+        }
+
+        [Benchmark]
+        public void VectorClock_comparisons_should_compare_notEquals_Concurrent_Middle()
+        {
+            CheckThunkFor(_vcAfterMiddle, _vcConcurrentMiddle, (clock, vectorClock) => NotEqual(clock, vectorClock), Iterations);
+        }
+    }
+}