Add Allocation Ratio column (dotnet#1859)

Co-authored-by: Adam Sitnik <[email protected]>

src/BenchmarkDotNet/Columns/BaselineAllocationRatioColumn.cs

@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using BenchmarkDotNet.Diagnosers;
+using BenchmarkDotNet.Mathematics;
+using BenchmarkDotNet.Reports;
+using BenchmarkDotNet.Running;
+using JetBrains.Annotations;
+
+namespace BenchmarkDotNet.Columns
+{
+    public class BaselineAllocationRatioColumn : BaselineCustomColumn
+    {
+        public override string Id => nameof(BaselineAllocationRatioColumn);
+        public override string ColumnName => "Alloc Ratio";
+
+        public override string GetValue(Summary summary, BenchmarkCase benchmarkCase, Statistics baseline, IReadOnlyDictionary<string, Metric> baselineMetrics,
+            Statistics current, IReadOnlyDictionary<string, Metric> currentMetrics, bool isBaseline)
+        {
+            double? ratio = GetAllocationRatio(currentMetrics, baselineMetrics);
+            double? invertedRatio = GetAllocationRatio(baselineMetrics, currentMetrics);
+
+            if (ratio == null)
+                return "NA";
+
+            var cultureInfo = summary.GetCultureInfo();
+            var ratioStyle = summary?.Style?.RatioStyle ?? RatioStyle.Value;
+
+            bool advancedPrecision = IsNonBaselinesPrecise(summary, baselineMetrics, benchmarkCase);
+            switch (ratioStyle)
+            {
+                case RatioStyle.Value:
+                    return ratio.Value.ToString(advancedPrecision ? "N3" : "N2", cultureInfo);
+                case RatioStyle.Percentage:
+                    return isBaseline
+                        ? ""
+                        : ratio.Value >= 1.0
+                            ? "+" + ((ratio.Value - 1.0) * 100).ToString(advancedPrecision ? "N1" : "N0", cultureInfo) + "%"
+                            : "-" + ((1.0 - ratio.Value) * 100).ToString(advancedPrecision ? "N1" : "N0", cultureInfo) + "%";
+                case RatioStyle.Trend:
+                    return isBaseline
+                        ? ""
+                        : ratio.Value >= 1.0
+                            ? ratio.Value.ToString(advancedPrecision ? "N3" : "N2", cultureInfo) + "x more"
+                            : invertedRatio == null
+                                ? "NA"
+                                : invertedRatio.Value.ToString(advancedPrecision ? "N3" : "N2", cultureInfo) + "x less";
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(summary), ratioStyle, "RatioStyle is not supported");
+            }
+        }
+
+        private static bool IsNonBaselinesPrecise(Summary summary, IReadOnlyDictionary<string, Metric> baselineMetric, BenchmarkCase benchmarkCase)
+        {
+            string logicalGroupKey = summary.GetLogicalGroupKey(benchmarkCase);
+            var nonBaselines = summary.GetNonBaselines(logicalGroupKey);
+            return nonBaselines.Any(c => GetAllocationRatio(summary[c].Metrics, baselineMetric) is > 0 and < 0.01);
+        }
+
+        private static double? GetAllocationRatio(
+            [CanBeNull] IReadOnlyDictionary<string, Metric> current,
+            [CanBeNull] IReadOnlyDictionary<string, Metric> baseline)
+        {
+            double? currentBytes = GetAllocatedBytes(current);
+            double? baselineBytes = GetAllocatedBytes(baseline);
+
+            if (currentBytes == null || baselineBytes == null)
+                return null;
+
+            if (baselineBytes == 0)
+                return null;
+
+            return currentBytes / baselineBytes;
+        }
+
+        private static double? GetAllocatedBytes([CanBeNull] IReadOnlyDictionary<string, Metric> metrics)
+        {
+            var metric = metrics?.Values.FirstOrDefault(m => m.Descriptor is AllocatedMemoryMetricDescriptor);
+            return metric?.Value;
+        }
+
+        public override ColumnCategory Category => ColumnCategory.Metric; //it should be displayed after Allocated column
+        public override int PriorityInCategory => AllocatedMemoryMetricDescriptor.Instance.PriorityInCategory + 1;
+        public override bool IsNumeric => true;
+        public override UnitType UnitType => UnitType.Dimensionless;
+        public override string Legend => "Allocated memory ratio distribution ([Current]/[Baseline])";
+    }
+}

src/BenchmarkDotNet/Columns/BaselineCustomColumn.cs

@@ -34,7 +34,7 @@ public abstract string GetValue(Summary summary, BenchmarkCase benchmarkCase, St
 
         public bool IsAvailable(Summary summary) => summary.HasBaselines();
         public bool AlwaysShow => true;
-        public ColumnCategory Category => ColumnCategory.Baseline;
+        public virtual ColumnCategory Category => ColumnCategory.Baseline;
         public abstract int PriorityInCategory { get; }
         public abstract bool IsNumeric { get; }
         public abstract UnitType UnitType { get; }

src/BenchmarkDotNet/Columns/DefaultColumnProvider.cs

@@ -63,13 +63,23 @@ public IEnumerable<IColumn> GetColumns(Summary summary)
                     bool hide = stdDevColumnValues.All(value => value == "0.00" || value == "0.01");
                     if (!hide)
                         yield return BaselineRatioColumn.RatioStdDev;
+
+                    if (HasMemoryDiagnoser(summary))
+                    {
+                        yield return new BaselineAllocationRatioColumn();
+                    }
                 }
             }
 
             private static bool NeedToShow(Summary summary, Func<Statistics, bool> check)
             {
                 return summary.Reports != null && summary.Reports.Any(r => r.ResultStatistics != null && check(r.ResultStatistics));
             }
+
+            private static bool HasMemoryDiagnoser(Summary summary)
+            {
+                return summary.BenchmarksCases.Any(c => c.Config.HasMemoryDiagnoser());
+            }
         }
 
         private class ParamsColumnProvider : IColumnProvider

src/BenchmarkDotNet/Diagnosers/AllocatedMemoryMetricDescriptor.cs

@@ -0,0 +1,20 @@
+using System;
+using BenchmarkDotNet.Columns;
+using BenchmarkDotNet.Reports;
+
+namespace BenchmarkDotNet.Diagnosers
+{
+    internal class AllocatedMemoryMetricDescriptor : IMetricDescriptor
+    {
+        internal static readonly IMetricDescriptor Instance = new AllocatedMemoryMetricDescriptor();
+
+        public string Id => "Allocated Memory";
+        public string DisplayName => "Allocated";
+        public string Legend => "Allocated memory per single operation (managed only, inclusive, 1KB = 1024B)";
+        public string NumberFormat => "0.##";
+        public UnitType UnitType => UnitType.Size;
+        public string Unit => SizeUnit.B.Name;
+        public bool TheGreaterTheBetter => false;
+        public int PriorityInCategory => GC.MaxGeneration + 1;
+    }
+}

src/BenchmarkDotNet/Diagnosers/MemoryDiagnoser.cs

@@ -45,20 +45,6 @@ public IEnumerable<Metric> ProcessResults(DiagnoserResults diagnoserResults)
             yield return new Metric(AllocatedMemoryMetricDescriptor.Instance, diagnoserResults.GcStats.GetBytesAllocatedPerOperation(diagnoserResults.BenchmarkCase));
         }
 
-        private class AllocatedMemoryMetricDescriptor : IMetricDescriptor
-        {
-            internal static readonly IMetricDescriptor Instance = new AllocatedMemoryMetricDescriptor();
-
-            public string Id => "Allocated Memory";
-            public string DisplayName => "Allocated";
-            public string Legend => "Allocated memory per single operation (managed only, inclusive, 1KB = 1024B)";
-            public string NumberFormat => "0.##";
-            public UnitType UnitType => UnitType.Size;
-            public string Unit => SizeUnit.B.Name;
-            public bool TheGreaterTheBetter => false;
-            public int PriorityInCategory => GC.MaxGeneration + 1;
-        }
-
         private class GarbageCollectionsMetricDescriptor : IMetricDescriptor
         {
             internal static readonly IMetricDescriptor Gen0 = new GarbageCollectionsMetricDescriptor(0);