force High Performance Mode by default, fixes #1506 (#1885)

Author: YegorStepanov

src/BenchmarkDotNet/Jobs/EnvironmentMode.cs

@@ -14,7 +14,7 @@ public sealed class EnvironmentMode : JobMode<EnvironmentMode>
         public static readonly Characteristic<IntPtr> AffinityCharacteristic = CreateCharacteristic<IntPtr>(nameof(Affinity));
         public static readonly Characteristic<GcMode> GcCharacteristic = CreateCharacteristic<GcMode>(nameof(Gc));
         public static readonly Characteristic<IReadOnlyList<EnvironmentVariable>> EnvironmentVariablesCharacteristic = CreateCharacteristic<IReadOnlyList<EnvironmentVariable>>(nameof(EnvironmentVariables));
-        public static readonly Characteristic<Guid> PowerPlanModeCharacteristic = CreateCharacteristic<Guid>(nameof(PowerPlanMode));
+        public static readonly Characteristic<Guid?> PowerPlanModeCharacteristic = CreateCharacteristic<Guid?>(nameof(PowerPlanMode));
 
         public static readonly EnvironmentMode LegacyJitX86 = new EnvironmentMode(nameof(LegacyJitX86), Jit.LegacyJit, Platform.X86).Freeze();
         public static readonly EnvironmentMode LegacyJitX64 = new EnvironmentMode(nameof(LegacyJitX64), Jit.LegacyJit, Platform.X64).Freeze();
@@ -89,7 +89,7 @@ public IReadOnlyList<EnvironmentVariable> EnvironmentVariables
         /// Power Plan Mode
         /// </summary>
         /// <remarks>Supported only on Windows.</remarks>
-        public Guid PowerPlanMode
+        public Guid? PowerPlanMode
         {
             get => PowerPlanModeCharacteristic[this];
             set => PowerPlanModeCharacteristic[this] = value;

src/BenchmarkDotNet/Running/BenchmarkRunnerClean.cs

@@ -148,7 +148,8 @@ private static Summary Run(BenchmarkRunInfo benchmarkRunInfo,
             {
                 foreach (var benchmark in benchmarks)
                 {
-                    powerManagementApplier.ApplyPerformancePlan(benchmark.Job.Environment.PowerPlanMode);
+                    powerManagementApplier.ApplyPerformancePlan(benchmark.Job.Environment.PowerPlanMode
+                        ?? benchmark.Job.ResolveValue(EnvironmentMode.PowerPlanModeCharacteristic, EnvironmentResolver.Instance).GetValueOrDefault());
 
                     var info = buildResults[benchmark];
                     var buildResult = info.buildResult;

src/BenchmarkDotNet/Running/PowerManagementApplier.cs

@@ -36,7 +36,7 @@ internal void ApplyPerformancePlan(Guid id)
             if (!RuntimeInformation.IsWindows() || id == Guid.Empty)
                 return;
 
-            if (!powerPlanChanged && id != UserPowerPlan)
+            if (id != UserPowerPlan)
                 ApplyPlanByGuid(id);
             else
                 ApplyUserPowerPlan();