Pools renamed to FixedCapacityPools. Other fixed capacity collections added. Queues, concurrent queues and standard stacks replaced with fixed capacity stacks. MethodImplOptions.AggressiveInlining and .AggressiveOptimization added to simple methods and getters / setters. Variables optimized in few places.

PerfectNumbers.Core/Gpu/Accelerators/AcceleratorStreamPool.cs

@@ -1,4 +1,4 @@
-using System.Collections.Concurrent;
+using System.Runtime.CompilerServices;
 using ILGPU.Runtime;
 
 namespace PerfectNumbers.Core.Gpu.Accelerators;
@@ -7,13 +7,14 @@ public static class AcceleratorStreamPool
 {
 	private static readonly Accelerator[] _accelerators = AcceleratorPool.Shared.Accelerators;
 	private static readonly SemaphoreSlim[] _locks = new SemaphoreSlim[PerfectNumberConstants.RollingAccelerators];
-	private static readonly ConcurrentQueue<AcceleratorStream>[] _streams = new ConcurrentQueue<AcceleratorStream> [PerfectNumberConstants.RollingAccelerators];
+	private static readonly ConcurrentFixedCapacityStack<AcceleratorStream>[] _streams = new ConcurrentFixedCapacityStack<AcceleratorStream>[PerfectNumberConstants.RollingAccelerators];
 
 	private static SemaphoreSlim CreateLock() => new(PerfectNumberConstants.ThreadsByAccelerator);
 
 
 	// private static int _rented;
 
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
 	public static AcceleratorStream Rent(int acceleratorIndex)
 	{
 		var streamLock = _locks[acceleratorIndex];
@@ -21,22 +22,23 @@ public static class AcceleratorStreamPool
 
 		streamLock.Wait();
 
-		return queue.TryDequeue(out var stream)
+		return queue.Pop() is { } stream
 			? stream
 			: _accelerators[acceleratorIndex].CreateStream();
 	}
 
+		[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
 	public static void Return(int acceleratorIndex, AcceleratorStream stream)
 	{
 		var streamLock = _locks[acceleratorIndex];
 		var queue = _streams[acceleratorIndex];
-		queue.Enqueue(stream);
+		queue.Push(stream);
 		streamLock.Release();
 	}
 
 	public static void WarmUp(int acceleratorIndex)
 	{
-		_streams[acceleratorIndex] = new();
+		_streams[acceleratorIndex] = new(PerfectNumberConstants.DefaultPoolCapacity);
 		_locks[acceleratorIndex] = CreateLock();
 	}
 }

PerfectNumbers.Core/Gpu/Accelerators/PrimeOrderCalculatorAccelerator.cs

@@ -1,4 +1,3 @@
-using System.Collections.Concurrent;
 using System.Runtime.CompilerServices;
 using ILGPU;
 using ILGPU.Runtime;
@@ -11,34 +10,31 @@ public sealed class PrimeOrderCalculatorAccelerator
 	#region Pool
 
 	// [ThreadStatic]
-	private static ConcurrentQueue<PrimeOrderCalculatorAccelerator>? _pool;
+	private static ConcurrentFixedCapacityStack<PrimeOrderCalculatorAccelerator>? _pool;
 
 	[MethodImpl(MethodImplOptions.AggressiveInlining)]
 	public static PrimeOrderCalculatorAccelerator Rent(int primeTesterCapacity)
 	{
-		var pool = _pool ??= [];
-		if (!pool.TryDequeue(out var gpu))
-		{
-			int acceleratorIndex = AcceleratorPool.Shared.Rent();
-			gpu = new(acceleratorIndex, PerfectNumberConstants.DefaultFactorsBuffer, primeTesterCapacity, PerfectNumberConstants.DefaultSmallPrimeFactorSlotCount, PerfectNumberConstants.DefaultSpecialMaxFactorCapacity);
-		}
-		else
+		var pool = _pool ??= new(PerfectNumberConstants.DefaultThreadPoolCapacity);
+		if (pool.Pop() is { } gpu)
 		{
 			gpu.EnsureCapacity(PerfectNumberConstants.DefaultFactorsBuffer, primeTesterCapacity);
+			return gpu;
 		}
 
-		return gpu;
+		int acceleratorIndex = AcceleratorPool.Shared.Rent();
+		return new(acceleratorIndex, PerfectNumberConstants.DefaultFactorsBuffer, primeTesterCapacity, PerfectNumberConstants.DefaultSmallPrimeFactorSlotCount, PerfectNumberConstants.DefaultSpecialMaxFactorCapacity);
 	}
 
 	[MethodImpl(MethodImplOptions.AggressiveInlining)]
-	public static void Return(PrimeOrderCalculatorAccelerator gpu) => _pool!.Enqueue(gpu);
+	public static void Return(PrimeOrderCalculatorAccelerator gpu) => _pool!.Push(gpu);
 
 	internal static void Clear()
 	{
 		var pool = _pool;
 		if (pool != null)
 		{
-			while (pool.TryDequeue(out var gpu))
+			while (pool.Pop() is { } gpu)
 			{
 				gpu.Dispose();
 			}
@@ -50,7 +46,7 @@ public sealed class PrimeOrderCalculatorAccelerator
 		var pool = _pool;
 		if (pool != null)
 		{
-			while (pool.TryDequeue(out var gpu))
+			while (pool.Pop() is { } gpu)
 			{
 				gpu.Dispose();
 			}