normalize time units

Author: Alex Peck

Benchly/ColumnChartExporter.cs

@@ -57,7 +57,7 @@ private IEnumerable<string> PerMethod(Summary summary)
                 var columnChartData = new TraceInfo()
                 {
                     Keys = new[] { report.BenchmarkCase.Descriptor.WorkloadMethodDisplayInfo },
-                    Values = new[] { report.Success ? ConvertNanosToMs(report.ResultStatistics.Mean) : 0 }
+                    Values = new[] { report.Success ? report.ResultStatistics.Mean : 0 }
                 };
 
                 ColumnChartRenderer.Render(new[] { columnChartData }, title, file, Info.Width, Info.Height, false);
@@ -80,7 +80,7 @@ private IEnumerable<string> PerJob(Summary summary)
             {
                 TraceName = r.BenchmarkCase.Job.ResolvedId,
                 Keys = new[] { r.BenchmarkCase.Descriptor.WorkloadMethodDisplayInfo },
-                Values = new[] { r.Success ? ConvertNanosToMs(r.ResultStatistics.Mean) : 0 }
+                Values = new[] { r.Success ? r.ResultStatistics.Mean : 0 }
             }).GroupBy(r => r.TraceName);
 
             var colors = ColorMap.GetColorList(Info);
@@ -127,7 +127,7 @@ private IEnumerable<string> NoParameterCombined(Summary summary)
             {
                 job = r.BenchmarkCase.Job.ResolvedId,
                 name = r.BenchmarkCase.Descriptor.WorkloadMethodDisplayInfo,
-                mean = r.Success ? ConvertNanosToMs(r.ResultStatistics.Mean) : 0
+                mean = r.Success ? r.ResultStatistics.Mean : 0
             })
             .GroupBy(r => r.job)
                 .Select(job => new TraceInfo() { Values = job.Select(j => j.mean).ToArray(), Keys = job.Select(j => j.name).ToArray(), TraceName = job.Key });
@@ -150,7 +150,7 @@ private IEnumerable<string> OneParameterCombined(Summary summary)
                     param = r.BenchmarkCase.Parameters.PrintInfo,
                     job = r.BenchmarkCase.Job.ResolvedId,
                     name = r.BenchmarkCase.Descriptor.WorkloadMethodDisplayInfo,
-                    mean = r.Success ? ConvertNanosToMs(r.ResultStatistics.Mean) : 0
+                    mean = r.Success ? r.ResultStatistics.Mean : 0
                 })
                 .GroupBy(r => r.param)
                 .Select(bp => new SubPlot()
@@ -164,7 +164,7 @@ private IEnumerable<string> OneParameterCombined(Summary summary)
                             Values = j.Select(j => j.mean).ToArray(), 
                             Keys = j.Select(j => j.name).ToArray(),
                         }).ToList()
-                });
+                }).ToList();
 
             var colors2 = ColorMap.GetColorList(Info);
             ColumnChartRenderer.Render(subPlots, title, file, Info.Width, Info.Height, colors2);
@@ -174,9 +174,9 @@ private IEnumerable<string> OneParameterCombined(Summary summary)
 
         // internal measurements are in nanos
         // https://github.com/dotnet/BenchmarkDotNet/blob/e4d37d03c0b1ef14e7bde224970bd0fc547fd95a/src/BenchmarkDotNet/Templates/BuildPlots.R#L63-L75
-        private static double ConvertNanosToMs(double nanos)
-        {
-            return nanos * 0.000001;
-        }
+        //private static double ConvertNanosToMs(double nanos)
+        //{
+        //    return nanos * 0.000001;
+        //}
     }
 }

Benchly/ColumnChartRenderer.cs

@@ -31,7 +31,7 @@ internal class ColumnChartRenderer
     {
         public static void Render(IEnumerable<TraceInfo> traces, string title, string file, int width, int height, bool showLegend)
         {
-            // TODO: pre-process to determine best units
+            var timeUnit = TimeNormalization.Normalize(traces);
 
             var charts = traces
                         .Select((cd, i) => Chart2D.Chart.Column<double, string, string, double, double>(
@@ -42,15 +42,15 @@ public static void Render(IEnumerable<TraceInfo> traces, string title, string fi
                         .WithLegendGroup(cd.TraceName, showLegend));
 
             Chart.Combine(charts)
-                    .WithAxisTitles($"Latency (ms)")
+                    .WithAxisTitles($"Latency ({timeUnit})")
                     .WithoutVerticalGridlines()
                     .WithLayout(title)
                     .SaveSVG(file, Width: width, Height: height);
         }
 
         public static void Render(IEnumerable<SubPlot> subPlot, string title, string file, int width, int height, Color[] colors)
         {
-            // TODO: pre-process to determine best units
+            var timeUnit = TimeNormalization.Normalize(subPlot.SelectMany(sp => sp.Traces));
 
             // make a grid with 1 row, n columns, where n is number of params
             // y axis only on first chart
@@ -99,7 +99,7 @@ public static void Render(IEnumerable<SubPlot> subPlot, string title, string fil
                 .Grid<IEnumerable<GenericChart.GenericChart>>(1, subPlot.Count(), Pattern: pattern).Invoke(gridCharts)
                 .WithAnnotations(annotations)
                 .WithoutVerticalGridlines()
-                .WithAxisTitles("Time (ms)")
+                .WithAxisTitles($"Time ({timeUnit})")
                 .WithLayout(title)
                 .SaveSVG(file, Width: width, Height: height);
         }

Benchly/TimeNormalization.cs

@@ -0,0 +1,42 @@
+
+namespace Benchly
+{
+    internal class TimeNormalization
+    {
+        public static string Normalize(IEnumerable<TraceInfo> traces)
+        {
+            var max = traces.SelectMany(t => t.Values).Max();
+
+            string timeUnit = "ns";
+
+            if (max > 1_000_000_000)
+            {
+                Reduce(traces, 0.000000001);
+                timeUnit = "s";
+            }
+            else if (max > 1_000_000)
+            {
+                Reduce(traces, 0.000001);
+                timeUnit = "ms";
+            }
+            else if (max > 1_000)
+            {
+                Reduce(traces, 0.001);
+                timeUnit = "μs";
+            }
+
+            return timeUnit;
+        }
+
+        private static void Reduce(IEnumerable<TraceInfo> traces, double factor)
+        {
+            foreach (var plot in traces)
+            {
+                for (int i = 0; i < plot.Values.Length; i++)
+                {
+                    plot.Values[i] *= factor;
+                }
+            }
+        }
+    }
+}