From a226ae10cb95775771fd0c3f7146765ffc46c909 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Lema=C5=84czyk?= <marek@lemanczyk.eu>
Date: Tue, 21 Oct 2025 20:52:21 +0200
Subject: [PATCH] Stop clearing pooled buffers inside rent helpers

---
 PerfectNumbers.Core/MersenneDivisorCycles.cs  |  3 +++
 .../PrimeOrderCalculator.Cpu.cs               |  5 ++++
 PerfectNumbers.Core/ThreadStaticPools.cs      | 27 +------------------
 3 files changed, 9 insertions(+), 26 deletions(-)

diff --git a/PerfectNumbers.Core/MersenneDivisorCycles.cs b/PerfectNumbers.Core/MersenneDivisorCycles.cs
index 942af1a..b0e677e 100644
--- a/PerfectNumbers.Core/MersenneDivisorCycles.cs
+++ b/PerfectNumbers.Core/MersenneDivisorCycles.cs
@@ -322,6 +322,7 @@ public class MersenneDivisorCycles
             primeOrderFailed = false;
         }
 
+        factorCounts.Clear();
         ThreadStaticPools.ReturnFactorCountDictionary(factorCounts);
         return success;
     }
@@ -339,6 +340,7 @@ public class MersenneDivisorCycles
         bool success = TryFactorIntoCountsInternal(value, scratch);
         if (!success)
         {
+            scratch.Clear();
             ThreadStaticPools.ReturnFactorScratchDictionary(scratch);
             return false;
         }
@@ -349,6 +351,7 @@ public class MersenneDivisorCycles
             AddFactor(counts, pair.Key, pair.Value);
         }
 
+        scratch.Clear();
         ThreadStaticPools.ReturnFactorScratchDictionary(scratch);
         return true;
     }
diff --git a/PerfectNumbers.Core/PrimeOrderCalculator.Cpu.cs b/PerfectNumbers.Core/PrimeOrderCalculator.Cpu.cs
index 8bf676b..abbad24 100644
--- a/PerfectNumbers.Core/PrimeOrderCalculator.Cpu.cs
+++ b/PerfectNumbers.Core/PrimeOrderCalculator.Cpu.cs
@@ -521,6 +521,7 @@ internal static partial class PrimeOrderCalculator
 			BuildCandidates(order, factorArray, orderFactors.Count, candidates, capacity);
 			if (candidates.Count == 0)
 			{
+				candidates.Clear();
 				ThreadStaticPools.ReturnUlongList(candidates);
 				return false;
 			}
@@ -623,6 +624,7 @@ internal static partial class PrimeOrderCalculator
 						pool.Return(gpuPool, clearArray: false);
 					}
 
+					candidates.Clear();
 					ThreadStaticPools.ReturnUlongList(candidates);
 					ThreadStaticPools.ReturnExponentStepper(powStepper);
 					result = candidate;
@@ -637,6 +639,7 @@ internal static partial class PrimeOrderCalculator
 				index += batchSize;
 			}
 
+			candidates.Clear();
 			ThreadStaticPools.ReturnUlongList(candidates);
 			ThreadStaticPools.ReturnExponentStepper(powStepper);
 			// DebugLog("No candidate confirmed");
@@ -1030,6 +1033,7 @@ internal static partial class PrimeOrderCalculator
 				}
 
 				factorCount = copyIndex;
+				counts.Clear();
 				ThreadStaticPools.ReturnUlongIntDictionary(counts);
 				counts = null;
 			}
@@ -1231,6 +1235,7 @@ internal static partial class PrimeOrderCalculator
 
 		if (counts is not null)
 		{
+			counts.Clear();
 			ThreadStaticPools.ReturnUlongIntDictionary(counts);
 		}
 
diff --git a/PerfectNumbers.Core/ThreadStaticPools.cs b/PerfectNumbers.Core/ThreadStaticPools.cs
index 8191676..f8b07cc 100644
--- a/PerfectNumbers.Core/ThreadStaticPools.cs
+++ b/PerfectNumbers.Core/ThreadStaticPools.cs
@@ -129,11 +129,6 @@ namespace PerfectNumbers.Core
                     int lastIndex = poolCount - 1;
                     List<ulong> list = pool[lastIndex];
                     pool.RemoveAt(lastIndex);
-                    if (list.Count > 0)
-                    {
-                        list.Clear();
-                    }
-
                     if (list.Capacity < capacityHint)
                     {
                         list.Capacity = capacityHint;
@@ -174,11 +169,6 @@ namespace PerfectNumbers.Core
                     int lastIndex = poolCount - 1;
                     List<PrimeOrderCalculator.PendingEntry> list = pool[lastIndex];
                     pool.RemoveAt(lastIndex);
-                    if (list.Count > 0)
-                    {
-                        list.Clear();
-                    }
-
                     if (list.Capacity < capacityHint)
                     {
                         list.Capacity = capacityHint;
@@ -219,14 +209,8 @@ namespace PerfectNumbers.Core
                     int lastIndex = poolCount - 1;
                     Stack<ulong> stack = pool[lastIndex];
                     pool.RemoveAt(lastIndex);
-                    int stackCount = stack.Count;
-                    if (stackCount > 0)
-                    {
-                        stack.Clear();
-                        stackCount = 0;
-                    }
 
-                    if (stackCount < capacityHint)
+                    if (stack.Count < capacityHint)
                     {
                         stack.EnsureCapacity(capacityHint);
                     }
@@ -266,11 +250,6 @@ namespace PerfectNumbers.Core
                     int lastIndex = poolCount - 1;
                     Dictionary<ulong, int> dictionary = pool[lastIndex];
                     pool.RemoveAt(lastIndex);
-                    if (dictionary.Count > 0)
-                    {
-                        dictionary.Clear();
-                    }
-
                     dictionary.EnsureCapacity(capacityHint);
 
                     return dictionary;
@@ -306,14 +285,12 @@ namespace PerfectNumbers.Core
             }
 
             _factorCountDictionary = null;
-            dictionary.Clear();
             return dictionary;
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void ReturnFactorCountDictionary(Dictionary<ulong, int> dictionary)
         {
-            dictionary.Clear();
             _factorCountDictionary = dictionary;
         }
 
@@ -330,14 +307,12 @@ namespace PerfectNumbers.Core
             }
 
             _factorScratchDictionary = null;
-            dictionary.Clear();
             return dictionary;
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void ReturnFactorScratchDictionary(Dictionary<ulong, int> dictionary)
         {
-            dictionary.Clear();
             _factorScratchDictionary = dictionary;
         }