Initial PollardRho implementation for GPU. Added pool for accelerator streams shared across the threads. GPU processing performance and stabilization improvements. GpuUInt128.BinaryGcd switched to the version which outperformed other in benchmarks.

PerfectNumbers.Core/Gpu/Accelerators/AcceleratorStreamPool.cs

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+using System.Collections.Concurrent;
+using ILGPU.Runtime;
+
+namespace PerfectNumbers.Core.Gpu.Accelerators;
+
+public static class AcceleratorStreamPool
+{
+	private static readonly ConcurrentDictionary<Accelerator, ConcurrentQueue<AcceleratorStream>> _streams = new(20_480, PerfectNumberConstants.RollingAccelerators);
+	// private static readonly ConcurrentDictionary<Accelerator, AcceleratorStream> _streams = new(AcceleratorPool.Shared.Accelerators.ToDictionary(static x => x, CreateStream));
+
+	private static SemaphoreSlim CreateLock() => new(PerfectNumberConstants.ThreadsByStream);
+	private static AcceleratorStream CreateStream(Accelerator accelerator) => accelerator.CreateStream();
+
+	private static readonly ConcurrentDictionary<Accelerator, SemaphoreSlim> _locks = new(AcceleratorPool.Shared.Accelerators.ToDictionary(x => x, static x => CreateLock()));
+
+	public static AcceleratorStream Rent(Accelerator accelerator)
+	{
+		var streamLock = _locks.GetOrAdd(accelerator, static _ => new SemaphoreSlim(PerfectNumberConstants.ThreadsByStream));
+
+		streamLock.Wait();
+		var queue = _streams.GetOrAdd(accelerator, static _ => new());
+
+		return queue.TryDequeue(out var stream)
+			? stream
+			: accelerator.CreateStream();
+	}
+
+	public static void Return(AcceleratorStream stream)
+	{
+		Accelerator accelerator = stream.Accelerator;
+		var streamLock = _locks.GetOrAdd(accelerator, static _ => CreateLock());
+		var queue = _streams.GetOrAdd(accelerator, static _ => new());
+		queue.Enqueue(stream);
+		streamLock.Release();
+	}
+}