Refactored engine JIT stage.

Author: timcassell

src/BenchmarkDotNet/Engines/Engine.cs

@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-using BenchmarkDotNet.Characteristics;
+using System.Diagnostics;
 using BenchmarkDotNet.Jobs;
 using BenchmarkDotNet.Mathematics;
 using BenchmarkDotNet.Reports;
@@ -9,22 +9,31 @@
 
 namespace BenchmarkDotNet.Engines
 {
-    internal abstract class EngineActualStage(IterationMode iterationMode) : EngineStage(IterationStage.Actual, iterationMode)
+    internal abstract class EngineActualStage(IterationMode iterationMode, long invokeCount, int unrollFactor, EngineParameters parameters) : EngineStage(IterationStage.Actual, iterationMode, parameters)
     {
         internal const int MaxOverheadIterationCount = 20;
 
-        internal static EngineActualStage GetOverhead(IEngine engine)
-            => new EngineActualStageAuto(engine.TargetJob, engine.Resolver, IterationMode.Overhead);
+        internal readonly long invokeCount = invokeCount;
+        internal readonly int unrollFactor = unrollFactor;
 
-        internal static EngineActualStage GetWorkload(IEngine engine, RunStrategy strategy)
+        internal static EngineActualStage GetOverhead(long invokeCount, int unrollFactor, EngineParameters parameters)
+            => new EngineActualStageAuto(IterationMode.Overhead, invokeCount, unrollFactor, parameters);
+
+        internal static EngineActualStage GetWorkload(RunStrategy strategy, long invokeCount, int unrollFactor, EngineParameters parameters)
         {
-            var targetJob = engine.TargetJob;
+            var targetJob = parameters.TargetJob;
             int? iterationCount = targetJob.ResolveValueAsNullable(RunMode.IterationCountCharacteristic);
             const int DefaultWorkloadCount = 10;
             return iterationCount == null && strategy != RunStrategy.Monitoring
-                ?  new EngineActualStageAuto(targetJob, engine.Resolver, IterationMode.Workload)
-                :  new EngineActualStageSpecific(iterationCount ?? DefaultWorkloadCount, IterationMode.Workload);
+                ? new EngineActualStageAuto(IterationMode.Workload, invokeCount, unrollFactor, parameters)
+                : new EngineActualStageSpecific(iterationCount ?? DefaultWorkloadCount, IterationMode.Workload, invokeCount, unrollFactor, parameters);
         }
+
+        protected IterationData GetIterationData()
+            => new(Mode, Stage, ++iterationIndex, invokeCount, unrollFactor, parameters.IterationSetupAction, parameters.IterationCleanupAction,
+                Mode == IterationMode.Workload
+                ? unrollFactor == 1 ? parameters.WorkloadActionNoUnroll : parameters.WorkloadActionUnroll
+                : unrollFactor == 1 ? parameters.OverheadActionNoUnroll : parameters.OverheadActionUnroll);
     }
 
     internal sealed class EngineActualStageAuto : EngineActualStage
@@ -37,22 +46,23 @@ internal sealed class EngineActualStageAuto : EngineActualStage
         private readonly List<Measurement> measurementsForStatistics;
         private int iterationCounter = 0;
 
-        public EngineActualStageAuto(Job targetJob, IResolver resolver, IterationMode iterationMode) : base(iterationMode)
+        public EngineActualStageAuto(IterationMode iterationMode, long invokeCount, int unrollFactor, EngineParameters parameters) : base(iterationMode, invokeCount, unrollFactor, parameters)
         {
-            maxRelativeError = targetJob.ResolveValue(AccuracyMode.MaxRelativeErrorCharacteristic, resolver);
-            maxAbsoluteError = targetJob.ResolveValueAsNullable(AccuracyMode.MaxAbsoluteErrorCharacteristic);
-            outlierMode = targetJob.ResolveValue(AccuracyMode.OutlierModeCharacteristic, resolver);
-            minIterationCount = targetJob.ResolveValue(RunMode.MinIterationCountCharacteristic, resolver);
-            maxIterationCount = targetJob.ResolveValue(RunMode.MaxIterationCountCharacteristic, resolver);
+            maxRelativeError = parameters.TargetJob.ResolveValue(AccuracyMode.MaxRelativeErrorCharacteristic, parameters.Resolver);
+            maxAbsoluteError = parameters.TargetJob.ResolveValueAsNullable(AccuracyMode.MaxAbsoluteErrorCharacteristic);
+            outlierMode = parameters.TargetJob.ResolveValue(AccuracyMode.OutlierModeCharacteristic, parameters.Resolver);
+            minIterationCount = parameters.TargetJob.ResolveValue(RunMode.MinIterationCountCharacteristic, parameters.Resolver);
+            maxIterationCount = parameters.TargetJob.ResolveValue(RunMode.MaxIterationCountCharacteristic, parameters.Resolver);
             measurementsForStatistics = GetMeasurementList();
         }
 
         internal override List<Measurement> GetMeasurementList() => new(maxIterationCount);
 
-        internal override bool GetShouldRunIteration(List<Measurement> measurements, ref long invokeCount)
+        internal override bool GetShouldRunIteration(List<Measurement> measurements, out IterationData iterationData)
         {
             if (measurements.Count == 0)
             {
+                iterationData = GetIterationData();
                 return true;
             }
 
@@ -72,25 +82,36 @@ internal override bool GetShouldRunIteration(List<Measurement> measurements, ref
 
             if (iterationCounter >= minIterationCount && actualError < maxError)
             {
+                iterationData = default;
                 return false;
             }
 
             if (iterationCounter >= maxIterationCount || isOverhead && iterationCounter >= MaxOverheadIterationCount)
             {
+                iterationData = default;
                 return false;
             }
 
+            iterationData = GetIterationData();
             return true;
         }
     }
 
-    internal sealed class EngineActualStageSpecific(int maxIterationCount, IterationMode iterationMode) : EngineActualStage(iterationMode)
+    internal sealed class EngineActualStageSpecific(int maxIterationCount, IterationMode iterationMode, long invokeCount, int unrollFactor, EngineParameters parameters)
+        : EngineActualStage(iterationMode, invokeCount, unrollFactor, parameters)
     {
-        private int iterationCount = 0;
-
         internal override List<Measurement> GetMeasurementList() => new(maxIterationCount);
 
-        internal override bool GetShouldRunIteration(List<Measurement> measurements, ref long invokeCount)
-            => ++iterationCount <= maxIterationCount;
+        internal override bool GetShouldRunIteration(List<Measurement> measurements, out IterationData iterationData)
+        {
+            if (iterationIndex < maxIterationCount)
+            {
+                iterationData = GetIterationData();
+                return true;
+            }
+
+            iterationData = default;
+            return false;
+        }
     }
 }

src/BenchmarkDotNet/Engines/EngineActualStage.cs

@@ -1,130 +1,13 @@
-using System;
-using BenchmarkDotNet.Jobs;
-using Perfolizer.Horology;
-
 namespace BenchmarkDotNet.Engines
 {
     public class EngineFactory : IEngineFactory
     {
         public IEngine CreateReadyToRun(EngineParameters engineParameters)
         {
-            if (engineParameters.WorkloadActionNoUnroll == null)
-                throw new ArgumentNullException(nameof(engineParameters.WorkloadActionNoUnroll));
-            if (engineParameters.WorkloadActionUnroll == null)
-                throw new ArgumentNullException(nameof(engineParameters.WorkloadActionUnroll));
-            if (engineParameters.Dummy1Action == null)
-                throw new ArgumentNullException(nameof(engineParameters.Dummy1Action));
-            if (engineParameters.Dummy2Action == null)
-                throw new ArgumentNullException(nameof(engineParameters.Dummy2Action));
-            if (engineParameters.Dummy3Action == null)
-                throw new ArgumentNullException(nameof(engineParameters.Dummy3Action));
-            if (engineParameters.OverheadActionNoUnroll == null)
-                throw new ArgumentNullException(nameof(engineParameters.OverheadActionNoUnroll));
-            if (engineParameters.OverheadActionUnroll == null)
-                throw new ArgumentNullException(nameof(engineParameters.OverheadActionUnroll));
-            if (engineParameters.TargetJob == null)
-                throw new ArgumentNullException(nameof(engineParameters.TargetJob));
-
+            // TODO: Move GlobalSetup/Cleanup to Engine.Run.
             engineParameters.GlobalSetupAction?.Invoke(); // whatever the settings are, we MUST call global setup here, the global cleanup is part of Engine's Dispose
 
-            if (!engineParameters.NeedsJitting) // just create the engine, do NOT jit
-                return CreateMultiActionEngine(engineParameters);
-
-            int jitIndex = 0;
-
-            if (engineParameters.HasInvocationCount || engineParameters.HasUnrollFactor) // it's a job with explicit configuration, just create the engine and jit it
-            {
-                var warmedUpMultiActionEngine = CreateMultiActionEngine(engineParameters);
-
-                DeadCodeEliminationHelper.KeepAliveWithoutBoxing(Jit(warmedUpMultiActionEngine, ++jitIndex, invokeCount: engineParameters.UnrollFactor, unrollFactor: engineParameters.UnrollFactor));
-
-                return warmedUpMultiActionEngine;
-            }
-
-            var singleActionEngine = CreateSingleActionEngine(engineParameters);
-            var singleInvocationTime = Jit(singleActionEngine, ++jitIndex, invokeCount: 1, unrollFactor: 1);
-            double timesPerIteration = engineParameters.IterationTime / singleInvocationTime; // how many times can we run given benchmark per iteration
-
-            if ((timesPerIteration < 1.5) && (singleInvocationTime < TimeInterval.FromSeconds(10.0)))
-            {
-                // if the Jitting took more than IterationTime/1.5 but still less than 10s (a magic number based on observations of reported bugs)
-                // we call it one more time to see if Jitting itself has not dominated the first invocation
-                // if it did, it should NOT be a single invocation engine (see #837, #1337, #1338, and #1780)
-                singleInvocationTime = Jit(singleActionEngine, ++jitIndex, invokeCount: 1, unrollFactor: 1);
-                timesPerIteration = engineParameters.IterationTime / singleInvocationTime;
-            }
-
-            // executing once takes longer than iteration time => long running benchmark, needs no pilot and no overhead
-            // Or executing twice would put us well past the iteration time ==> needs no pilot and no overhead
-            if (timesPerIteration < 1.5)
-                return singleActionEngine;
-
-            int defaultUnrollFactor = Job.Default.ResolveValue(RunMode.UnrollFactorCharacteristic, EngineParameters.DefaultResolver);
-            int roundedUpTimesPerIteration = (int)Math.Ceiling(timesPerIteration);
-
-            if (roundedUpTimesPerIteration < defaultUnrollFactor) // if we run it defaultUnrollFactor times per iteration, it's going to take longer than IterationTime
-            {
-                var needsPilot = engineParameters.TargetJob
-                    .WithUnrollFactor(1) // we don't want to use unroll factor!
-                    .WithMinInvokeCount(2) // the minimum is 2 (not the default 4 which can be too much and not 1 which we already know is not enough)
-                    .WithEvaluateOverhead(false); // it's something very time consuming, it overhead is too small compared to total time
-
-                return CreateEngine(engineParameters, needsPilot, engineParameters.OverheadActionNoUnroll, engineParameters.WorkloadActionNoUnroll);
-            }
-
-            var multiActionEngine = CreateMultiActionEngine(engineParameters);
-
-            DeadCodeEliminationHelper.KeepAliveWithoutBoxing(Jit(multiActionEngine, ++jitIndex, invokeCount: defaultUnrollFactor, unrollFactor: defaultUnrollFactor));
-
-            return multiActionEngine;
+            return new Engine(engineParameters);
         }
-
-        /// <returns>the time it took to run the benchmark</returns>
-        private static TimeInterval Jit(Engine engine, int jitIndex, int invokeCount, int unrollFactor)
-        {
-            engine.Dummy1Action.Invoke();
-
-            DeadCodeEliminationHelper.KeepAliveWithoutBoxing(engine.RunIteration(new IterationData(IterationMode.Overhead, IterationStage.Jitting, jitIndex, invokeCount, unrollFactor))); // don't forget to JIT idle
-
-            engine.Dummy2Action.Invoke();
-
-            var result = engine.RunIteration(new IterationData(IterationMode.Workload, IterationStage.Jitting, jitIndex, invokeCount, unrollFactor));
-
-            engine.Dummy3Action.Invoke();
-
-            engine.WriteLine();
-
-            return TimeInterval.FromNanoseconds(result.Nanoseconds);
-        }
-
-        private static Engine CreateMultiActionEngine(EngineParameters engineParameters)
-            => CreateEngine(engineParameters, engineParameters.TargetJob, engineParameters.OverheadActionUnroll, engineParameters.WorkloadActionUnroll);
-
-        private static Engine CreateSingleActionEngine(EngineParameters engineParameters)
-            => CreateEngine(engineParameters,
-                engineParameters.TargetJob
-                    .WithInvocationCount(1).WithUnrollFactor(1) // run the benchmark exactly once per iteration
-                    .WithEvaluateOverhead(false), // it's something very time consuming, it overhead is too small compared to total time
-                    // todo: consider if we should set the warmup count to 2
-                engineParameters.OverheadActionNoUnroll,
-                engineParameters.WorkloadActionNoUnroll);
-
-        private static Engine CreateEngine(EngineParameters engineParameters, Job job, Action<long> idle, Action<long> main)
-            => new Engine(
-                engineParameters.Host,
-                EngineParameters.DefaultResolver,
-                engineParameters.Dummy1Action,
-                engineParameters.Dummy2Action,
-                engineParameters.Dummy3Action,
-                idle,
-                main,
-                job,
-                engineParameters.GlobalSetupAction,
-                engineParameters.GlobalCleanupAction,
-                engineParameters.IterationSetupAction,
-                engineParameters.IterationCleanupAction,
-                engineParameters.OperationsPerInvoke,
-                engineParameters.MeasureExtraStats,
-                engineParameters.BenchmarkName);
     }
 }