Expose new EventCounter APIs (#23808)

* rename BaseCounter to DiagnosticCounter

* Change MetaData->Metadata

* Make EventSource and Name a property for counter classes

* Make the counter APIs public

* fix build errors

* Change float to double

* Few cleanups, fix test

* fix GetMetadataString

* PR feedback

* More PR feedback

Author: sywhang

src/System.Private.CoreLib/shared/System.Private.CoreLib.Shared.projitems

@@ -908,7 +908,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\Tracing\ActivityTracker.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\Tracing\BaseCounter.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\Tracing\DiagnosticCounter.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\Tracing\CounterGroup.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\Tracing\CounterPayload.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Diagnostics\Tracing\EventActivityOptions.cs" />

src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/CounterGroup.cs

@@ -20,22 +20,22 @@ namespace System.Diagnostics.Tracing
     internal class CounterGroup
     {
         private readonly EventSource _eventSource;
-        private readonly List<BaseCounter> _counters;
+        private readonly List<DiagnosticCounter> _counters;
 
         internal CounterGroup(EventSource eventSource)
         {
             _eventSource = eventSource;
-            _counters = new List<BaseCounter>();
+            _counters = new List<DiagnosticCounter>();
             RegisterCommandCallback();
         }
 
-        internal void Add(BaseCounter eventCounter)
+        internal void Add(DiagnosticCounter eventCounter)
         {
             lock (this) // Lock the CounterGroup
                 _counters.Add(eventCounter);
         }
 
-        internal void Remove(BaseCounter eventCounter)
+        internal void Remove(DiagnosticCounter eventCounter)
         {
             lock (this) // Lock the CounterGroup
                 _counters.Remove(eventCounter);

src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/CounterPayload.cs

@@ -17,72 +17,26 @@ namespace Microsoft.Diagnostics.Tracing
 namespace System.Diagnostics.Tracing
 #endif
 {
-    // TODO: This should be removed as we make the new payloads public
-    [EventData]
-    internal class EventCounterPayload : IEnumerable<KeyValuePair<string, object>>
-    {
-        public string Name { get; set; }
-
-        public float Mean { get; set; }
-
-        public float StandardDeviation { get; set; }
-
-        public int Count { get; set; }
-
-        public float Min { get; set; }
-
-        public float Max { get; set; }
-
-        public float IntervalSec { get; internal set; }
-
-        #region Implementation of the IEnumerable interface
-
-        public IEnumerator<KeyValuePair<string, object>> GetEnumerator()
-        {
-            return ForEnumeration.GetEnumerator();
-        }
-
-        IEnumerator IEnumerable.GetEnumerator()
-        {
-            return ForEnumeration.GetEnumerator();
-        }
-
-        private IEnumerable<KeyValuePair<string, object>> ForEnumeration
-        {
-            get
-            {
-                yield return new KeyValuePair<string, object>("Name", Name);
-                yield return new KeyValuePair<string, object>("Mean", Mean);
-                yield return new KeyValuePair<string, object>("StandardDeviation", StandardDeviation);
-                yield return new KeyValuePair<string, object>("Count", Count);
-                yield return new KeyValuePair<string, object>("Min", Min);
-                yield return new KeyValuePair<string, object>("Max", Max);
-            }
-        }
-
-        #endregion // Implementation of the IEnumerable interface
-    }
-
     [EventData]
     internal class CounterPayload : IEnumerable<KeyValuePair<string, object>>
     {
         public string Name { get; set; }
 
         public string DisplayName { get; set; }
 
-        public float Mean { get; set; }
+        public double Mean { get; set; }
 
-        public float StandardDeviation { get; set; }
+        public double StandardDeviation { get; set; }
 
         public int Count { get; set; }
 
-        public float Min { get; set; }
+        public double Min { get; set; }
 
-        public float Max { get; set; }
+        public double Max { get; set; }
 
         public float IntervalSec { get; internal set; }
 
-        public string MetaData { get; set; }
+        public string Metadata { get; set; }
 
         #region Implementation of the IEnumerable interface
 
@@ -110,7 +64,7 @@ private IEnumerable<KeyValuePair<string, object>> ForEnumeration
                 yield return new KeyValuePair<string, object>("IntervalSec", IntervalSec);
                 yield return new KeyValuePair<string, object>("Series", $"Interval={IntervalSec}");
                 yield return new KeyValuePair<string, object>("CounterType", "Mean");
-                yield return new KeyValuePair<string, object>("MetaData", MetaData);
+                yield return new KeyValuePair<string, object>("Metadata", Metadata);
             }
         }
 
@@ -126,11 +80,11 @@ internal class IncrementingCounterPayload : IEnumerable<KeyValuePair<string, obj
 
         public string DisplayRateTimeScale { get; set; }
 
-        public float Increment { get; set; }
+        public double Increment { get; set; }
 
         public float IntervalSec { get; internal set; }
 
-        public string MetaData { get; set; }
+        public string Metadata { get; set; }
 
         #region Implementation of the IEnumerable interface
 
@@ -155,7 +109,7 @@ private IEnumerable<KeyValuePair<string, object>> ForEnumeration
                 yield return new KeyValuePair<string, object>("IntervalSec", IntervalSec);
                 yield return new KeyValuePair<string, object>("Series", $"Interval={IntervalSec}");
                 yield return new KeyValuePair<string, object>("CounterType", "Sum");
-                yield return new KeyValuePair<string, object>("MetaData", MetaData);
+                yield return new KeyValuePair<string, object>("Metadata", Metadata);
             }
         }
 

src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/BaseCounter.cs renamed to src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/DiagnosticCounter.cs

@@ -19,34 +19,33 @@ namespace System.Diagnostics.Tracing
 #endif
 {
     /// <summary>
-    /// BaseCounter is an abstract class that serves as the parent class for various Counter* classes, 
+    /// DiagnosticCounter is an abstract class that serves as the parent class for various Counter* classes, 
     /// namely EventCounter, PollingCounter, IncrementingEventCounter, and IncrementingPollingCounter.
     /// </summary>
-    public abstract class BaseCounter : IDisposable
+    public abstract class DiagnosticCounter : IDisposable
     {
         /// <summary>
         /// All Counters live as long as the EventSource that they are attached to unless they are
         /// explicitly Disposed.   
         /// </summary>
         /// <param name="name">The name.</param>
         /// <param name="eventSource">The event source.</param>
-        public BaseCounter(string name, EventSource eventSource)
+        public DiagnosticCounter(string name, EventSource eventSource)
         {
             if (name == null)
             {
-                throw new ArgumentNullException(nameof(_name));
+                throw new ArgumentNullException(nameof(Name));
             }
 
             if (eventSource == null)
             {
-                throw new ArgumentNullException(nameof(eventSource));
+                throw new ArgumentNullException(nameof(EventSource));
             }
 
             _group = CounterGroup.GetCounterGroup(eventSource);
             _group.Add(this);
-            _eventSource = eventSource;
-            _name = name;
-            _metaData = new Dictionary<string, string>();
+            Name = name;
+            EventSource = eventSource;
         }
 
         /// <summary>
@@ -67,38 +66,45 @@ public void Dispose()
         /// <summary>
         /// Adds a key-value metadata to the EventCounter that will be included as a part of the payload
         /// </summary>
-        internal void AddMetaData(string key, string value)
+        public void AddMetadata(string key, string value)
         {
             lock (MyLock)
             {
-                _metaData.Add(key, value);
+                _metadata = _metadata ?? new Dictionary<string, string>();
+                _metadata.Add(key, value);
             }
         }
 
-        internal string DisplayName { get; set; }
+        public string DisplayName { get; set; }
 
-        #region private implementation
+        public string Name { get; }
+
+        public EventSource EventSource { get; }
 
-        internal readonly string _name;
+        #region private implementation
 
         private CounterGroup _group;
-        private Dictionary<string, string> _metaData;
-        internal EventSource _eventSource;
+        private Dictionary<string, string> _metadata;
 
         internal abstract void WritePayload(float intervalSec);
 
         // arbitrarily we use name as the lock object.  
-        internal object MyLock { get { return _name; } }
+        internal object MyLock { get { return Name; } }
 
         internal void ReportOutOfBandMessage(string message)
         {
-            _eventSource.ReportOutOfBandMessage(message, true);
+            EventSource.ReportOutOfBandMessage(message, true);
         }
 
-        internal string GetMetaDataString()
+        internal string GetMetadataString()
         {
+            if (_metadata == null)
+            {
+                return "";
+            }
+
             StringBuilder sb = new StringBuilder("");
-            foreach(KeyValuePair<string, string> kvPair in _metaData)
+            foreach(KeyValuePair<string, string> kvPair in _metadata)
             {
                 sb.Append($"{kvPair.Key}:{kvPair.Value},");
             }

src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/EventCounter.cs

@@ -26,7 +26,7 @@ namespace System.Diagnostics.Tracing
     /// See https://github.com/dotnet/corefx/blob/master/src/System.Diagnostics.Tracing/tests/BasicEventSourceTest/TestEventCounter.cs
     /// which shows tests, which are also useful in seeing actual use.  
     /// </summary>
-    public partial class EventCounter : BaseCounter
+    public partial class EventCounter : DiagnosticCounter
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="EventCounter"/> class.
@@ -37,8 +37,8 @@ public partial class EventCounter : BaseCounter
         /// <param name="eventSource">The event source.</param>
         public EventCounter(string name, EventSource eventSource) : base(name, eventSource)
         {
-            _min = float.PositiveInfinity;
-            _max = float.NegativeInfinity;
+            _min = double.PositiveInfinity;
+            _max = double.NegativeInfinity;
 
             InitializeBuffer();
         }
@@ -49,22 +49,27 @@ public EventCounter(string name, EventSource eventSource) : base(name, eventSour
         /// </summary>
         /// <param name="value">The value.</param>
         public void WriteMetric(float value)
+        {
+            Enqueue((double)value);
+        }
+
+        public void WriteMetric(double value)
         {
             Enqueue(value);
         }
 
-        public override string ToString() => $"EventCounter '{_name}' Count {_count} Mean {(((double)_sum) / _count).ToString("n3")}";
+        public override string ToString() => $"EventCounter '{Name}' Count {_count} Mean {(_sum / _count).ToString("n3")}";
 
         #region Statistics Calculation
 
         // Statistics
         private int _count;
-        private float _sum;
-        private float _sumSquared;
-        private float _min;
-        private float _max;
+        private double _sum;
+        private double _sumSquared;
+        private double _min;
+        private double _max;
 
-        internal void OnMetricWritten(float value)
+        internal void OnMetricWritten(double value)
         {
             Debug.Assert(Monitor.IsEntered(MyLock));
             _sum += value;
@@ -83,14 +88,13 @@ internal override void WritePayload(float intervalSec)
             lock (MyLock)
             {
                 Flush();
-                EventCounterPayload payload = new EventCounterPayload();
-                payload.Name = _name;
+                CounterPayload payload = new CounterPayload();
                 payload.Count = _count;
                 payload.IntervalSec = intervalSec;
                 if (0 < _count)
                 {
                     payload.Mean = _sum / _count;
-                    payload.StandardDeviation = (float)Math.Sqrt(_sumSquared / _count - _sum * _sum / _count / _count);
+                    payload.StandardDeviation = Math.Sqrt(_sumSquared / _count - _sum * _sum / _count / _count);
                 }
                 else
                 {
@@ -99,8 +103,12 @@ internal override void WritePayload(float intervalSec)
                 }
                 payload.Min = _min;
                 payload.Max = _max;
+                
+                payload.Metadata = GetMetadataString();
+                payload.DisplayName = DisplayName;
+                payload.Name = Name;
                 ResetStatistics();
-                _eventSource.Write("EventCounters", new EventSourceOptions() { Level = EventLevel.LogAlways }, new EventCounterPayloadType(payload));
+                EventSource.Write("EventCounters", new EventSourceOptions() { Level = EventLevel.LogAlways }, new CounterPayloadType(payload));
             }
         }
         private void ResetStatistics()
@@ -109,35 +117,35 @@ private void ResetStatistics()
             _count = 0;
             _sum = 0;
             _sumSquared = 0;
-            _min = float.PositiveInfinity;
-            _max = float.NegativeInfinity;
+            _min = double.PositiveInfinity;
+            _max = double.NegativeInfinity;
         }
 
         #endregion // Statistics Calculation
 
         // Values buffering
         private const int BufferedSize = 10;
-        private const float UnusedBufferSlotValue = float.NegativeInfinity;
+        private const double UnusedBufferSlotValue = double.NegativeInfinity;
         private const int UnsetIndex = -1;
-        private volatile float[] _bufferedValues;
+        private volatile double[] _bufferedValues;
         private volatile int _bufferedValuesIndex;
 
         private void InitializeBuffer()
         {
-            _bufferedValues = new float[BufferedSize];
+            _bufferedValues = new double[BufferedSize];
             for (int i = 0; i < _bufferedValues.Length; i++)
             {
                 _bufferedValues[i] = UnusedBufferSlotValue;
             }
         }
 
-        protected void Enqueue(float value)
+        private void Enqueue(double value)
         {
             // It is possible that two threads read the same bufferedValuesIndex, but only one will be able to write the slot, so that is okay.
             int i = _bufferedValuesIndex;
             while (true)
             {
-                float result = Interlocked.CompareExchange(ref _bufferedValues[i], value, UnusedBufferSlotValue);
+                double result = Interlocked.CompareExchange(ref _bufferedValues[i], value, UnusedBufferSlotValue);
                 i++;
                 if (_bufferedValues.Length <= i)
                 {
@@ -178,10 +186,10 @@ protected void Flush()
     /// This is the payload that is sent in the with EventSource.Write
     /// </summary>
     [EventData]
-    class EventCounterPayloadType
+    class CounterPayloadType
     {
-        public EventCounterPayloadType(EventCounterPayload payload) { Payload = payload; }
-        public EventCounterPayload Payload { get; set; }
+        public CounterPayloadType(CounterPayload payload) { Payload = payload; }
+        public CounterPayload Payload { get; set; }
     }
 
 }