Tasks will now save calculations progress and resume calculation upon restart.

PerfectNumbers.Core/Gpu/Accelerators/AcceleratorStreamPool.cs

@@ -16,10 +16,10 @@ public static class AcceleratorStreamPool
 
 	public static AcceleratorStream Rent(int acceleratorIndex)
 	{
-		// var streamLock = _locks[acceleratorIndex];
+		var streamLock = _locks[acceleratorIndex];
 		var queue = _streams[acceleratorIndex];
 
-		// streamLock.Wait();
+		streamLock.Wait();
 
 		return queue.TryDequeue(out var stream)
 			? stream
@@ -28,10 +28,10 @@ public static class AcceleratorStreamPool
 
 	public static void Return(int acceleratorIndex, AcceleratorStream stream)
 	{
-		// var streamLock = _locks[acceleratorIndex];
+		var streamLock = _locks[acceleratorIndex];
 		var queue = _streams[acceleratorIndex];
 		queue.Enqueue(stream);
-		// streamLock.Release();
+		streamLock.Release();
 	}
 
 	public static void WarmUp(int acceleratorIndex)

PerfectNumbers.Core/Gpu/GpuPrimeWorkLimiter.cs

@@ -1,12 +1,15 @@
+using PerfectNumbers.Core;
+
 namespace PerfectNumbers.Core.Gpu;
 
 public static class GpuPrimeWorkLimiter
 {
-	private static SemaphoreSlim _semaphore = new(1, int.MaxValue);
+	private static readonly TimeSpan _pauseBetweenChecks = TimeSpan.FromSeconds(2);
+	private static PollingSemaphore _semaphore = new(1, _pauseBetweenChecks);
 	private static int _currentLimit = 1;
 
-	public static void Acquire() { } // => _semaphore.Wait();
-	public static void Release() { }// => _semaphore.Release();
+	public static void Acquire() => _semaphore.Wait();
+	public static void Release() => _semaphore.Release();
 
 	public static void SetLimit(int value)
     {
@@ -18,13 +21,13 @@ public static class GpuPrimeWorkLimiter
         if (value == _currentLimit)
         {
             return;
-        }
+	}
 
         // TODO: Switch to a shared limiter implementation with GpuWorkLimiter so we can coordinate CPU/GPU prime work using
         // the same semaphore pool without reallocating per adjustment.
-        var previous = _semaphore;
-        _semaphore = new SemaphoreSlim(value, value);
+        // var previous = _semaphore;
+        _semaphore = new PollingSemaphore(value, _pauseBetweenChecks);
         _currentLimit = value;
-        previous.Dispose();
+        // previous.Dispose();
     }
 }

PerfectNumbers.Core/Gpu/MersenneNumberDivisorByDivisorGpuTester.cs

@@ -43,6 +43,17 @@ public sealed partial class MersenneNumberDivisorByDivisorGpuTester : IMersenneN
 		set => _minK = value < 1UL ? 1UL : value;
 	}
 
+	public string? StateFilePath { get; set; }
+
+	public void ResetStateTracking()
+	{
+	}
+
+	public void ResumeFromState(ulong lastSavedK)
+	{
+		_minK = lastSavedK + 1UL;
+	}
+
 	public void ConfigureFromMaxPrime(ulong maxPrime)
 	{
 		// EvenPerfectBitScanner configures the GPU tester once before scanning and never mutates the configuration afterwards,