Note some SOS dependencies, small fixes in hill climbing to make equi…

…valent to coreclr

src/coreclr/src/System.Private.CoreLib/src/System/Threading/ThreadPool.CoreCLR.cs

@@ -165,7 +165,9 @@ public UnmanagedThreadPoolWorkItem(IntPtr callback, IntPtr state)
 
     public static partial class ThreadPool
     {
+        // SOS's ThreadPool command depends on this name
         internal static readonly bool UsePortableThreadPool = InitializeConfigAndDetermineUsePortableThreadPool();
+
         internal static bool SupportsTimeSensitiveWorkItems => UsePortableThreadPool;
 
         // This needs to be initialized after UsePortableThreadPool above, as it may depend on UsePortableThreadPool and the

src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.HillClimbing.cs

@@ -12,14 +12,15 @@ internal partial class PortableThreadPool
         /// </summary>
         private partial class HillClimbing
         {
-            private static readonly Lazy<HillClimbing> s_threadPoolHillClimber = new Lazy<HillClimbing>(CreateHillClimber, true);
-            public static HillClimbing ThreadPoolHillClimber => s_threadPoolHillClimber.Value;
-
+            private const int LogCapacity = 200;
             private const int DefaultSampleIntervalMsLow = 10;
             private const int DefaultSampleIntervalMsHigh = 200;
 
             public static readonly bool IsDisabled = AppContextConfigHelper.GetBooleanConfig("System.Threading.ThreadPool.HillClimbing.Disable", false);
 
+            // SOS's ThreadPool command depends on this name
+            public static readonly HillClimbing ThreadPoolHillClimber = CreateHillClimber();
+
             private static HillClimbing CreateHillClimber()
             {
                 // Default values pulled from CoreCLR
@@ -38,8 +39,8 @@ private static HillClimbing CreateHillClimber()
                     maxSampleError: AppContextConfigHelper.GetInt32Config("System.Threading.ThreadPool.HillClimbing.MaxSampleErrorPercent", 15, false) / 100.0
                 );
             }
-            private const int LogCapacity = 200;
 
+            // SOS's ThreadPool command depends on the enum values
             public enum StateOrTransition
             {
                 Warmup,
@@ -52,13 +53,14 @@ public enum StateOrTransition
                 ThreadTimedOut,
             }
 
+            // SOS's ThreadPool command depends on the names of all fields
             private struct LogEntry
             {
                 public int tickCount;
                 public StateOrTransition stateOrTransition;
                 public int newControlSetting;
                 public int lastHistoryCount;
-                public double lastHistoryMean;
+                public float lastHistoryMean;
             }
 
             private readonly int _wavePeriod;
@@ -89,9 +91,9 @@ private struct LogEntry
 
             private readonly Random _randomIntervalGenerator = new Random();
 
-            private readonly LogEntry[] _log = new LogEntry[LogCapacity];
-            private int _logStart;
-            private int _logSize;
+            private readonly LogEntry[] _log = new LogEntry[LogCapacity]; // SOS's ThreadPool command depends on this name
+            private int _logStart; // SOS's ThreadPool command depends on this name
+            private int _logSize; // SOS's ThreadPool command depends on this name
 
             public HillClimbing(int wavePeriod, int maxWaveMagnitude, double waveMagnitudeMultiplier, int waveHistorySize, double targetThroughputRatio,
                 double targetSignalToNoiseRatio, double maxChangePerSecond, double maxChangePerSample, int sampleIntervalMsLow, int sampleIntervalMsHigh,
@@ -417,8 +419,8 @@ private void LogTransition(int newThreadCount, double throughput, StateOrTransit
                 entry.tickCount = Environment.TickCount;
                 entry.stateOrTransition = stateOrTransition;
                 entry.newControlSetting = newThreadCount;
-                entry.lastHistoryCount = ((int)Math.Min(_totalSamples, _samplesToMeasure) / _wavePeriod) * _wavePeriod;
-                entry.lastHistoryMean = throughput;
+                entry.lastHistoryCount = (int)(Math.Min(_totalSamples, _samplesToMeasure) / _wavePeriod) * _wavePeriod;
+                entry.lastHistoryMean = (float)throughput;
 
                 _logSize++;
 

src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.ThreadCounts.cs

@@ -12,11 +12,12 @@ internal partial class PortableThreadPool
         /// </summary>
         private struct ThreadCounts
         {
+            // SOS's ThreadPool command depends on this layout
             private const byte NumProcessingWorkShift = 0;
             private const byte NumExistingThreadsShift = 16;
             private const byte NumThreadsGoalShift = 32;
 
-            private ulong _data;
+            private ulong _data; // SOS's ThreadPool command depends on this name
 
             private ThreadCounts(ulong data) => _data = data;
 

src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.cs

@@ -33,11 +33,12 @@ internal sealed partial class PortableThreadPool
         private static object? t_completionCountObject;
 
 #pragma warning disable IDE1006 // Naming Styles
-        // The singleton must be initialized after the static variables above, as the constructor may be dependent on them
+        // The singleton must be initialized after the static variables above, as the constructor may be dependent on them.
+        // SOS's ThreadPool command depends on this name.
         public static readonly PortableThreadPool ThreadPoolInstance = new PortableThreadPool();
 #pragma warning restore IDE1006 // Naming Styles
 
-        private int _cpuUtilization = 0;
+        private int _cpuUtilization = 0; // SOS's ThreadPool command depends on this name
         private short _minThreads;
         private short _maxThreads;
         private readonly LowLevelLock _maxMinThreadLock = new LowLevelLock();
@@ -46,7 +47,7 @@ internal sealed partial class PortableThreadPool
         private struct CacheLineSeparated
         {
             [FieldOffset(Internal.PaddingHelpers.CACHE_LINE_SIZE * 1)]
-            public ThreadCounts counts;
+            public ThreadCounts counts; // SOS's ThreadPool command depends on this name
             [FieldOffset(Internal.PaddingHelpers.CACHE_LINE_SIZE * 2)]
             public int lastDequeueTime;
             [FieldOffset(Internal.PaddingHelpers.CACHE_LINE_SIZE * 3)]
@@ -61,7 +62,7 @@ private struct CacheLineSeparated
             public int gateThreadRunningState;
         }
 
-        private CacheLineSeparated _separated;
+        private CacheLineSeparated _separated; // SOS's ThreadPool command depends on this name
         private long _currentSampleStartTime;
         private readonly ThreadInt64PersistentCounter _completionCounter = new ThreadInt64PersistentCounter();
         private int _threadAdjustmentIntervalMs;