Merge pull request #152 from mlemanczyk/codex/optimize-accelerator-allocation-for-mersennedivisorcycles

Remove GPU fallback from context pool

PerfectNumbers.Core/Gpu/GpuContextPool.cs

@@ -145,8 +145,7 @@ public static class GpuContextPool
 
         public object ExecutionLock => _ctx.ExecutionLock;
 
-
+        internal void ReturnToPool()
-                public void Dispose()
         {
             if (disposed)
             {
@@ -156,6 +155,10 @@ public static class GpuContextPool
             Return(_ctx);
             disposed = true;
         }
-    }
-}
 
+        public void Dispose()
+        {
+            ReturnToPool();
+        }
+    }
+}

PerfectNumbers.Core/Gpu/GpuKernelPool.cs

@@ -396,7 +396,10 @@ public ref struct GpuKernelLease(IDisposable limiter, GpuContextLease gpu, Kerne
                 _stream?.Dispose();
                 _stream = null;
 
-                _gpu?.Dispose();
+                if (_gpu.HasValue)
+                {
+                    _gpu.Value.ReturnToPool();
+                }
                 _gpu = null;
 
                 _executionLock = null;

PerfectNumbers.Core/Gpu/PrimeOrderGpuHeuristics.cs

@@ -1715,10 +1715,10 @@ internal static partial class PrimeOrderGpuHeuristics
         GpuUInt128[]? rentedExponents = null;
         GpuUInt128[]? rentedResults = null;
         var lease = GpuKernelPool.GetKernel(useGpuOrder: true);
+        var execution = lease.EnterExecutionScope();
 
         try
         {
-            var execution = lease.EnterExecutionScope();
             Accelerator accelerator = lease.Accelerator;
             AcceleratorStream stream = lease.Stream;
             var kernel = GetPow2ModWideKernel(accelerator);
@@ -1755,7 +1755,6 @@ internal static partial class PrimeOrderGpuHeuristics
 
             exponentBuffer.Dispose();
             remainderBuffer.Dispose();
-            execution.Dispose();
             return true;
         }
         catch (Exception)
@@ -1775,6 +1774,7 @@ internal static partial class PrimeOrderGpuHeuristics
                 ArrayPool<GpuUInt128>.Shared.Return(rentedResults, clearArray: false);
             }
 
+            execution.Dispose();
             lease.Dispose();
         }
     }