Support out of proc Histogram Base 2 Exponential aggregation

THIRD-PARTY-NOTICES.TXT

@@ -90,6 +90,18 @@ freely, subject to the following restrictions:
 
 3. This notice may not be removed or altered from any source distribution.
 
+License notice for opentelemetry-dotnet
+---------------------------------------
+
+https://github.com/open-telemetry/opentelemetry-dotnet/blob/805dd6b4abfa18ef2706d04c30d0ed28dbc2955e/LICENSE.TXT#L1
+
+Apache License
+Version 2.0, January 2004
+http://www.apache.org/licenses/
+
+Copyright The OpenTelemetry Authors
+
+
 License notice for LinuxTracepoints
 -----------------------------------
 

src/libraries/System.Diagnostics.DiagnosticSource/src/Resources/Strings.resx

@@ -1,17 +1,17 @@
 <?xml version="1.0" encoding="utf-8"?>
 <root>
-  <!-- 
-    Microsoft ResX Schema 
-    
+  <!--
+    Microsoft ResX Schema
+
     Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
+
+    The primary goals of this format is to allow a simple XML format
+    that is mostly human readable. The generation and parsing of the
+    various data types are done through the TypeConverter classes
     associated with the data types.
-    
+
     Example:
-    
+
     ... ado.net/XML headers & schema ...
     <resheader name="resmimetype">text/microsoft-resx</resheader>
     <resheader name="version">2.0</resheader>
@@ -26,36 +26,36 @@
         <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
         <comment>This is a comment</comment>
     </data>
-                
-    There are any number of "resheader" rows that contain simple 
+
+    There are any number of "resheader" rows that contain simple
     name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
+
+    Each data row contains a name, and value. The row also contains a
+    type or mimetype. Type corresponds to a .NET class that support
+    text/value conversion through the TypeConverter architecture.
+    Classes that don't support this are serialized and stored with the
     mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
+
+    The mimetype is used for serialized objects, and tells the
+    ResXResourceReader how to depersist the object. This is currently not
     extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
+
+    Note - application/x-microsoft.net.object.binary.base64 is the format
+    that the ResXResourceWriter will generate, however the reader can
     read any of the formats listed below.
-    
+
     mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
             : and then encoded with base64 encoding.
-    
+
     mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
             : and then encoded with base64 encoding.
 
     mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
+    value   : The object must be serialized into a byte array
             : using a System.ComponentModel.TypeConverter
             : and then encoded with base64 encoding.
     -->
@@ -177,4 +177,10 @@
   <data name="InvalidHistogramExplicitBucketBoundaries" xml:space="preserve">
     <value>Histogram explicit bucket boundaries must be specified in ascending order and cannot contain duplicate values.</value>
   </data>
-</root>
+  <data name="InvalidHistogramScale" xml:space="preserve">
+    <value>Invalid scale value {0}. Scale must be greater than or equal to {1} and less than or equal to {2}.</value>
+  </data>
+  <data name="InvalidHistogramMaxBuckets" xml:space="preserve">
+    <value>Invalid Max buckets value {0}. Max buckets must be greater than or equal to {1}.</value>
+  </data>
+</root>

src/libraries/System.Diagnostics.DiagnosticSource/src/System.Diagnostics.DiagnosticSource.csproj

@@ -61,6 +61,8 @@ System.Diagnostics.DiagnosticSource</PackageDescription>
     <Compile Include="System\Diagnostics\Metrics\AggregationManager.cs" />
     <Compile Include="System\Diagnostics\Metrics\Aggregator.cs" />
     <Compile Include="System\Diagnostics\Metrics\AggregatorStore.cs" />
+    <Compile Include="System\Diagnostics\Metrics\Base2ExponentialHistogramAggregator.cs" />
+    <Compile Include="System\Diagnostics\Metrics\CircularBufferBuckets.cs" />
     <Compile Include="System\Diagnostics\Metrics\Counter.cs" />
     <Compile Include="System\Diagnostics\Metrics\ExponentialHistogramAggregator.cs" />
     <Compile Include="System\Diagnostics\Metrics\Gauge.cs" />

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Metrics/AggregationManager.cs

@@ -48,6 +48,7 @@ internal sealed class AggregationManager
         private DateTime _startTime;
         private DateTime _intervalStartTime;
         private DateTime _nextIntervalStartTime;
+        private Func<Aggregator?> _histogramAggregatorFactory = () => new ExponentialHistogramAggregator(s_defaultHistogramConfig);
 
         public AggregationManager(
             int maxTimeSeries,
@@ -120,6 +121,16 @@ private void Include(Predicate<Instrument> instrumentFilter)
             }
         }
 
+        public void SetHistogramAggregation(Func<Aggregator?> histogramAggregatorFactory)
+        {
+            lock (this)
+            {
+                // While this operation is atomic, we use a lock to ensure thread safety when it's accessed by other parts of the code.
+                // Using lock(this) guarantees that no other thread is interacting with the field concurrently.
+                _histogramAggregatorFactory = histogramAggregatorFactory;
+            }
+        }
+
         public AggregationManager SetCollectionPeriod(TimeSpan collectionPeriod)
         {
             // The caller, MetricsEventSource, is responsible for enforcing this
@@ -417,9 +428,7 @@ private void RemoveInstrumentState(Instrument instrument)
                     lock (this)
                     {
                         // checking currentHistograms first because avoiding unexpected increment of TimeSeries count.
-                        return (!CheckHistogramAllowed() || !CheckTimeSeriesAllowed()) ?
-                            null :
-                            new ExponentialHistogramAggregator(s_defaultHistogramConfig);
+                        return (!CheckHistogramAllowed() || !CheckTimeSeriesAllowed()) ? null : _histogramAggregatorFactory();
                     }
                 };
             }

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Metrics/Aggregator.cs

@@ -42,15 +42,77 @@ internal HistogramStatistics(QuantileValue[] quantiles, int count, double sum)
         public double Sum { get; }
     }
 
-    internal sealed class LabeledAggregationStatistics
+    /// <summary>
+    /// Represents the statistics of a base 2 exponential histogram.
+    /// </summary>
+    internal sealed class Base2ExponentialHistogramStatistics : IAggregationStatistics
     {
-        public LabeledAggregationStatistics(IAggregationStatistics stats, params KeyValuePair<string, string>[] labels)
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Base2ExponentialHistogramStatistics"/> class capturing the current collected statistics.
+        /// </summary>
+        /// <param name="scale">Maximum scale factor.</param>
+        /// <param name="zeroCount">The number of zero values in the histogram.</param>
+        /// <param name="sum">The sum of all values in the histogram.</param>
+        /// <param name="count">The count of all values in the histogram.</param>
+        /// <param name="min">The minimum value in the histogram.</param>
+        /// <param name="max">The maximum value in the histogram.</param>
+        /// <param name="buckets">The buckets in the histogram.</param>
+        internal Base2ExponentialHistogramStatistics(int scale, long zeroCount, double sum, long count, double min, double max, long[] buckets)
         {
-            AggregationStatistics = stats;
-            Labels = labels;
+            Scale = scale;
+            ZeroCount = zeroCount;
+            Sum = sum;
+            Count = count;
+            Minimum = min;
+            Maximum = max;
+            PositiveBuckets = buckets;
         }
 
-        public KeyValuePair<string, string>[] Labels { get; }
-        public IAggregationStatistics AggregationStatistics { get; }
+        /// <summary>
+        /// Gets the maximum scale factor.
+        /// </summary>
+        public int Scale { get; }
+
+        /// <summary>
+        /// Gets the number of zero values in the histogram.
+        /// </summary>
+        public long ZeroCount { get; }
+
+        /// <summary>
+        /// Gets the sum of all values in the histogram.
+        /// </summary>
+        public double Sum { get; }
+
+        /// <summary>
+        /// Gets the count of all values in the histogram.
+        /// </summary>
+        public long Count { get; }
+
+        /// <summary>
+        /// Gets the minimum value in the histogram.
+        /// </summary>
+        public double Minimum { get; }
+
+        /// <summary>
+        /// Gets the maximum value in the histogram.
+        /// </summary>
+        public double Maximum { get; }
+
+        /// <summary>
+        /// Gets the positive measurement buckets in the histogram.
+        /// </summary>
+        public long[] PositiveBuckets { get; }
     }
+
+    internal sealed class LabeledAggregationStatistics
+        {
+            public LabeledAggregationStatistics(IAggregationStatistics stats, params KeyValuePair<string, string>[] labels)
+            {
+                AggregationStatistics = stats;
+                Labels = labels;
+            }
+
+            public KeyValuePair<string, string>[] Labels { get; }
+            public IAggregationStatistics AggregationStatistics { get; }
+        }
 }