From c61df1c33b9a74e505b85d8af513c5a8d2934f12 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Lema=C5=84czyk?= <marek@lemanczyk.eu>
Date: Wed, 29 Oct 2025 19:21:32 +0100
Subject: [PATCH] Inline batch copies for GPU prime tester

---
 PerfectNumbers.Core/PrimeTester.cs | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/PerfectNumbers.Core/PrimeTester.cs b/PerfectNumbers.Core/PrimeTester.cs
index dc1e607..3832125 100644
--- a/PerfectNumbers.Core/PrimeTester.cs
+++ b/PerfectNumbers.Core/PrimeTester.cs
@@ -4,6 +4,7 @@ using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Numerics;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 using ILGPU;
 using ILGPU.Runtime;
 using PerfectNumbers.Core.Gpu;
@@ -117,11 +118,13 @@ public sealed class PrimeTester
 
                 var input = gpu.Input;
                 var output = gpu.Output;
+                var inputView = input.View;
+                var outputView = output.View;
 
-                input.View.CopyFromCPU(ref value, 1);
+                inputView.CopyFromCPU(ref value, 1);
                 kernel(
                                 1,
-                                input.View,
+                                inputView,
                                 gpu.DevicePrimesDefault.View,
                                 gpu.DevicePrimesLastOne.View,
                                 gpu.DevicePrimesLastSeven.View,
@@ -132,9 +135,9 @@ public sealed class PrimeTester
                                 gpu.DevicePrimesPow2LastSeven.View,
                                 gpu.DevicePrimesPow2LastThree.View,
                                 gpu.DevicePrimesPow2LastNine.View,
-                                output.View);
+                                outputView);
                 accelerator.Synchronize();
-                output.View.CopyToCPU(ref flag, 1);
+                outputView.CopyToCPU(ref flag, 1);
 
                 gpu.Dispose();
                 limiter.Dispose();
@@ -163,8 +166,8 @@ public static bool IsPrimeCpu(ulong n, CancellationToken ct)
 
                 var input = gpu.Input;
                 var output = gpu.Output;
-                ArrayPool<ulong> pool = ThreadStaticPools.UlongPool;
-                ulong[] temp = pool.Rent(batchSize);
+                var inputView = input.View;
+                var outputView = output.View;
 
                 int pos = 0;
                 while (pos < totalLength)
@@ -172,12 +175,13 @@ public static bool IsPrimeCpu(ulong n, CancellationToken ct)
                         int remaining = totalLength - pos;
                         int count = remaining > batchSize ? batchSize : remaining;
 
-                        values.Slice(pos, count).CopyTo(temp);
-                        input.View.CopyFromCPU(ref temp[0], count);
+                        var valueSlice = values.Slice(pos, count);
+                        ref ulong valueRef = ref MemoryMarshal.GetReference(valueSlice);
+                        inputView.CopyFromCPU(ref valueRef, count);
 
                         kernel(
                                 count,
-                                input.View,
+                                inputView,
                                 gpu.DevicePrimesDefault.View,
                                 gpu.DevicePrimesLastOne.View,
                                 gpu.DevicePrimesLastSeven.View,
@@ -188,15 +192,15 @@ public static bool IsPrimeCpu(ulong n, CancellationToken ct)
                                 gpu.DevicePrimesPow2LastSeven.View,
                                 gpu.DevicePrimesPow2LastThree.View,
                                 gpu.DevicePrimesPow2LastNine.View,
-                                output.View);
+                                outputView);
                         accelerator.Synchronize();
-                        output.View.CopyToCPU(ref results[pos], count);
+                        var resultSlice = results.Slice(pos, count);
+                        ref byte resultRef = ref MemoryMarshal.GetReference(resultSlice);
+                        outputView.CopyToCPU(ref resultRef, count);
 
                         pos += count;
                 }
 
-                pool.Return(temp, clearArray: false);
-
                 gpu.Dispose();
                 limiter.Dispose();
         }