Initial commit.

PerfectNumbers.Core/Gpu/GpuWorkLimiter.cs

@@ -0,0 +1,60 @@
+namespace PerfectNumbers.Core.Gpu;
+
+public static class GpuWorkLimiter
+{
+    private static SemaphoreSlim _semaphore = new(1, int.MaxValue);
+    private static readonly object _lock = new();
+    private static int _currentLimit = 1;
+
+    public static IDisposable Acquire()
+    {
+        var sem = _semaphore;
+        sem.Wait();
+        return new Releaser(sem);
+    }
+
+    public static void SetLimit(int value)
+    {
+        if (value < 1)
+        {
+            value = 1;
+        }
+
+        lock (_lock)
+        {
+            if (value == _currentLimit)
+            {
+                return;
+            }
+
+            // Swap to a new semaphore for the new limit. We intentionally
+            // do not dispose the old semaphore to avoid releasing handles
+            // that may still be in use by existing Releaser instances.
+            _semaphore = new SemaphoreSlim(value, value);
+            _currentLimit = value;
+        }
+    }
+
+    private sealed class Releaser : IDisposable
+    {
+        private readonly SemaphoreSlim _sem;
+        private bool _disposed;
+
+        public Releaser(SemaphoreSlim sem)
+        {
+            _sem = sem;
+        }
+
+        public void Dispose()
+        {
+            if (_disposed)
+            {
+                return;
+            }
+
+            _sem.Release();
+            _disposed = true;
+        }
+    }
+}
+