BitContradiction adjusted for p >= 138 mln, based on carry out analysis of the first 1024 columns.

PerfectNumbers.Core/Cpu/MersenneNumberDivisorByDivisorCpuTesterWithTemplate.cs

@@ -62,6 +62,9 @@ public struct MersenneNumberDivisorByDivisorCpuTesterWithTemplate() : IMersenneN
 	private GpuUInt128WorkSet _divisorScanGpuWorkSet;
 	private static readonly ConcurrentDictionary<ulong, byte> _checkedPow2MinusOne = new();
 	private ulong _currentPrime;
+#if WITH_PRUNE_STATS
+    private readonly TimeSpan _slowCalculationThreshold = TimeSpan.FromMilliseconds(700);
+#endif
 
 #if DEVICE_GPU && DivisorSet_BitContradiction
 	[MethodImpl(MethodImplOptions.AggressiveOptimization)]
@@ -5104,6 +5107,10 @@ public struct MersenneNumberDivisorByDivisorCpuTesterWithTemplate() : IMersenneN
 		BigInteger divisor = (step * currentK) + BigInteger.One;
 		_qBits = new int[(int)prime];
 		Stopwatch sw = new Stopwatch();
+#if WITH_PRUNE_STATS
+        var slowCalculationThreshold = _slowCalculationThreshold;
+#endif
+
 		// sw.Start();
 		while (true)
 		{
@@ -5143,6 +5150,13 @@ public struct MersenneNumberDivisorByDivisorCpuTesterWithTemplate() : IMersenneN
 			}
 			else
 			{
+#if WITH_PRUNE_STATS
+                if (sw.Elapsed >= slowCalculationThreshold)
+                {
+					Console.WriteLine($"SLOW CALCULATIONS: Prime {prime} ({sw.Elapsed}: {divisor})");
+					_consolePrintOut = 0;
+                }
+#else
 				var printToConsole = (_consolePrintOut++) == PerfectNumberConstants.ConsoleInterval;
 				if (printToConsole)
 				{
@@ -5152,6 +5166,7 @@ public struct MersenneNumberDivisorByDivisorCpuTesterWithTemplate() : IMersenneN
 					// sw.Reset();
 					// sw.Start();
 				}
+#endif
 			}
 
 #if DETAILED_LOG