mlemanczyk/even-perfect-numbers-scanner
1
0 Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Enable multi-threaded divisor scanning

Browse Source
This commit is contained in:
Marek Lemańczyk committed 2025-09-21 13:44:18 +02:00
1 parent 198b31f380
commit bf02826f7c
1 file changed
+168 -62
Download Patch File Download Diff File Expand all files Collapse all files
EvenPerfectBitScanner/Program.cs
+168 -62
View File
@@ -63,6 +63,22 @@ internal static class Program
internal bool DetailedCheck; internal bool DetailedCheck;
} }
private readonly struct PendingResult
{
internal PendingResult(ulong prime, bool detailedCheck, bool passedAllTests)
{
Prime = prime;
DetailedCheck = detailedCheck;
PassedAllTests = passedAllTests;
}
internal ulong Prime { get; }
internal bool DetailedCheck { get; }
internal bool PassedAllTests { get; }
}
private static unsafe void Main(string[] args) private static unsafe void Main(string[] args)
{ {
ulong currentP = InitialP; ulong currentP = InitialP;
@@ -646,7 +662,7 @@ internal static class Program
if (_useByDivisorMode) if (_useByDivisorMode)
{ {
RunByDivisorMode(filterList, divisorCyclesSearchLimit); RunByDivisorMode(filterList, divisorCyclesSearchLimit, threadCount);
FlushBuffer(); FlushBuffer();
StringBuilderPool.Return(_outputBuilder!); StringBuilderPool.Return(_outputBuilder!);
return; return;
@@ -734,7 +750,7 @@ internal static class Program
StringBuilderPool.Return(_outputBuilder!); StringBuilderPool.Return(_outputBuilder!);
} }
private static void RunByDivisorMode(List<ulong> primes, ulong divisorCyclesSearchLimit) private static void RunByDivisorMode(List<ulong> primes, ulong divisorCyclesSearchLimit, int threadCount)
{ {
if (primes.Count == 0) if (primes.Count == 0)
{ {
@@ -777,79 +793,77 @@ internal static class Program
return; return;
} }
object stateLock = new();
ulong divisorLimit = _byDivisorTester!.DivisorLimit;
ulong nextDivisor = 3UL;
bool divisorsExhausted = false;
ulong finalDivisorValue = 3UL;
int remainingStates = states.Count;
Task[] workers = new Task[Math.Max(1, threadCount)];
for (int i = 0; i < workers.Length; i++)
{
workers[i] = Task.Run(() =>
{
using var session = _byDivisorTester!.CreateDivisorSession(); using var session = _byDivisorTester!.CreateDivisorSession();
byte[] hitsBuffer = ArrayPool<byte>.Shared.Rent(states.Count); byte[] hitsBuffer = ArrayPool<byte>.Shared.Rent(states.Count);
ulong[] primeBuffer = ArrayPool<ulong>.Shared.Rent(states.Count); ulong[] primeBuffer = ArrayPool<ulong>.Shared.Rent(states.Count);
int[] indexBuffer = ArrayPool<int>.Shared.Rent(states.Count); int[] indexBuffer = ArrayPool<int>.Shared.Rent(states.Count);
List<PendingResult> completions = new(states.Count);
List<PendingResult> composites = new(states.Count);
try try
{ {
ulong divisor = 3UL;
ulong divisorLimit = _byDivisorTester!.DivisorLimit;
while (true) while (true)
{ {
bool anyPending = false; ulong divisor;
int activeCount = 0; int activeCount;
bool shouldTerminate;
bool hasWork;
for (int i = 0; i < states.Count; i++) lock (stateLock)
{ {
var state = states[i]; hasWork = TryAcquireDivisorWork(states, divisorLimit, primeBuffer, indexBuffer, completions, ref nextDivisor, ref divisorsExhausted, ref finalDivisorValue, ref remainingStates, out divisor, out activeCount, out shouldTerminate);
if (state.Completed)
{
continue;
} }
if (state.AllowedMax < divisor) if (completions.Count > 0)
{ {
state.Completed = true; foreach (PendingResult result in completions)
state.DetailedCheck = true;
states[i] = state;
PrintResult(state.Prime, searchedMersenne: true, detailedCheck: true, passedAllTests: true);
continue;
}
anyPending = true;
if (divisor > divisorLimit)
{ {
states[i] = state; PrintResult(result.Prime, searchedMersenne: true, detailedCheck: result.DetailedCheck, passedAllTests: result.PassedAllTests);
continue;
} }
primeBuffer[activeCount] = state.Prime; completions.Clear();
indexBuffer[activeCount] = i;
activeCount++;
states[i] = state;
} }
if (!anyPending || divisor > divisorLimit) if (!hasWork)
{
if (shouldTerminate)
{ {
break; break;
} }
if (activeCount == 0)
{
ulong nextDivisor = divisor + 2UL;
if (nextDivisor <= divisor)
{
break;
}
divisor = nextDivisor;
continue; continue;
} }
session.CheckDivisor(divisor, primeBuffer.AsSpan(0, activeCount), hitsBuffer.AsSpan(0, activeCount)); Span<byte> hitsSpan = hitsBuffer.AsSpan(0, activeCount);
hitsSpan.Clear();
session.CheckDivisor(divisor, primeBuffer.AsSpan(0, activeCount), hitsSpan);
for (int i = 0; i < activeCount; i++) bool exitAfterIteration;
composites.Clear();
lock (stateLock)
{ {
if (hitsBuffer[i] == 0) for (int j = 0; j < activeCount; j++)
{
if (hitsSpan[j] == 0)
{ {
continue; continue;
} }
int index = indexBuffer[i]; int index = indexBuffer[j];
var state = states[index]; var state = states[index];
if (state.Completed) if (state.Completed)
{ {
@@ -860,33 +874,67 @@ internal static class Program
state.Composite = true; state.Composite = true;
state.DetailedCheck = true; state.DetailedCheck = true;
states[index] = state; states[index] = state;
PrintResult(state.Prime, searchedMersenne: true, detailedCheck: true, passedAllTests: false); remainingStates--;
composites.Add(new PendingResult(state.Prime, state.DetailedCheck, false));
} }
bool remaining = false; exitAfterIteration = remainingStates == 0;
for (int i = 0; i < states.Count; i++) if (exitAfterIteration && !divisorsExhausted)
{ {
if (!states[i].Completed) divisorsExhausted = true;
{ finalDivisorValue = Math.Max(finalDivisorValue, nextDivisor);
remaining = true;
break;
} }
} }
if (!remaining) if (composites.Count > 0)
{
foreach (PendingResult result in composites)
{
PrintResult(result.Prime, searchedMersenne: true, detailedCheck: result.DetailedCheck, passedAllTests: result.PassedAllTests);
}
}
if (exitAfterIteration)
{ {
break; break;
} }
}
ulong next = divisor + 2UL; }
if (next <= divisor) finally
{ {
break; ArrayPool<int>.Shared.Return(indexBuffer, clearArray: true);
ArrayPool<ulong>.Shared.Return(primeBuffer, clearArray: true);
ArrayPool<byte>.Shared.Return(hitsBuffer, clearArray: true);
}
});
} }
divisor = next; Task.WaitAll(workers);
} }
private static bool TryAcquireDivisorWork(List<ByDivisorPrimeState> states, ulong divisorLimit, ulong[] primeBuffer, int[] indexBuffer, List<PendingResult> completions, ref ulong nextDivisor, ref bool divisorsExhausted, ref ulong finalDivisorValue, ref int remainingStates, out ulong divisor, out int activeCount, out bool shouldTerminate)
{
completions.Clear();
while (true)
{
if (remainingStates == 0)
{
divisor = 0UL;
activeCount = 0;
shouldTerminate = true;
return false;
}
if (divisorsExhausted || nextDivisor > divisorLimit)
{
if (!divisorsExhausted)
{
divisorsExhausted = true;
finalDivisorValue = nextDivisor;
}
ulong completionDivisor = finalDivisorValue;
for (int i = 0; i < states.Count; i++) for (int i = 0; i < states.Count; i++)
{ {
var state = states[i]; var state = states[i];
@@ -896,16 +944,74 @@ internal static class Program
} }
state.Completed = true; state.Completed = true;
state.DetailedCheck = divisor > state.AllowedMax; state.DetailedCheck = completionDivisor > state.AllowedMax;
states[i] = state; states[i] = state;
PrintResult(state.Prime, searchedMersenne: true, detailedCheck: state.DetailedCheck, passedAllTests: true); remainingStates--;
completions.Add(new PendingResult(state.Prime, state.DetailedCheck, true));
} }
divisor = 0UL;
activeCount = 0;
shouldTerminate = true;
return false;
} }
finally
ulong divisorValue = nextDivisor;
ulong candidate = divisorValue + 2UL;
if (candidate <= divisorValue)
{ {
ArrayPool<int>.Shared.Return(indexBuffer, clearArray: true); divisorsExhausted = true;
ArrayPool<ulong>.Shared.Return(primeBuffer, clearArray: true); finalDivisorValue = divisorValue;
ArrayPool<byte>.Shared.Return(hitsBuffer, clearArray: true); }
else
{
nextDivisor = candidate;
if (nextDivisor > divisorLimit)
{
divisorsExhausted = true;
finalDivisorValue = nextDivisor;
}
}
activeCount = 0;
for (int i = 0; i < states.Count; i++)
{
var state = states[i];
if (state.Completed)
{
continue;
}
if (state.AllowedMax < divisorValue)
{
state.Completed = true;
state.DetailedCheck = true;
states[i] = state;
remainingStates--;
completions.Add(new PendingResult(state.Prime, state.DetailedCheck, true));
continue;
}
primeBuffer[activeCount] = state.Prime;
indexBuffer[activeCount] = i;
activeCount++;
}
if (activeCount == 0)
{
if (completions.Count == 0)
{
continue;
}
divisor = 0UL;
shouldTerminate = remainingStates == 0 && (divisorsExhausted || nextDivisor > divisorLimit);
return false;
}
divisor = divisorValue;
shouldTerminate = false;
return true;
} }
} }