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

Reduce host hit detection overhead

Browse Source
This commit is contained in:
Marek Lemańczyk committed 2025-10-22 23:51:19 +02:00
1 parent 4d9158e8f3
commit faab60c2cd
2 files changed
+61 -11
Download Patch File Download Diff File Expand all files Collapse all files

No files matched your search

PerfectNumbers.Core/Gpu/Kernels/DivisorByDivisorKernels.cs
+19
View File
@@ -236,6 +236,25 @@ internal static class DivisorByDivisorKernels
Atomic.Max(ref compactedCount[0], storedCount);
}
public static void PublishFirstHitKernel(
Index1D index,
ArrayView<byte> hits,
ArrayView<int> firstHit)
{
int globalIndex = index;
// EvenPerfectBitScanner launches this auto-grouped kernel with an extent matching the hit view length,
// so the defensive guard stays commented out to keep the hot path branch-free.
// int length = (int)hits.Length;
// if (globalIndex >= length)
// {
// return;
// }
byte hitValue = hits[globalIndex];
int candidate = hitValue != 0 ? globalIndex : int.MaxValue;
Atomic.Min(ref firstHit[0], candidate);
}
public static void ComputeMontgomeryExponentKernel(Index1D index, MontgomeryDivisorData divisor, ArrayView<ulong> exponents, ArrayView<ulong> results)
{
ulong modulus = divisor.Modulus;
PerfectNumbers.Core/Gpu/MersenneNumberDivisorByDivisorGpuTester.cs
+42 -11
View File
@@ -29,6 +29,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
private readonly ConcurrentDictionary<Accelerator, Action<KernelConfig, Index1D, ArrayView<byte>, ArrayView<byte>, byte, byte>> _remainderScanKernelCache = new(AcceleratorReferenceComparer.Instance);
private readonly ConcurrentDictionary<Accelerator, Action<Index1D, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, byte, ArrayView<byte>>> _candidateMaskKernelCache = new(AcceleratorReferenceComparer.Instance);
private readonly ConcurrentDictionary<Accelerator, Action<KernelConfig, Index1D, ArrayView<byte>, ArrayView<ulong>, ArrayView<ulong>, ArrayView<int>>> _candidateCompactionKernelCache = new(AcceleratorReferenceComparer.Instance);
private readonly ConcurrentDictionary<Accelerator, Action<Index1D, ArrayView<byte>, ArrayView<int>>> _hitDetectionKernelCache = new(AcceleratorReferenceComparer.Instance);
private readonly ConcurrentDictionary<Accelerator, Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, ArrayView<GpuUInt128>, GpuUInt128, GpuUInt128>> _candidateGenerationKernelCache = new(AcceleratorReferenceComparer.Instance);
private readonly ConcurrentDictionary<Accelerator, ConcurrentBag<BatchResources>> _resourcePools = new(AcceleratorReferenceComparer.Instance);
private readonly ConcurrentBag<GpuContextPool.GpuContextLease> _acceleratorPool = new();
@@ -58,6 +59,11 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
accelerator,
acc => acc.LoadStreamKernel<Index1D, ArrayView<byte>, ArrayView<ulong>, ArrayView<ulong>, ArrayView<int>>(DivisorByDivisorKernels.CompactCandidateMaskKernel));
private Action<Index1D, ArrayView<byte>, ArrayView<int>> GetHitDetectionKernel(Accelerator accelerator) =>
_hitDetectionKernelCache.GetOrAdd(
accelerator,
acc => acc.LoadAutoGroupedStreamKernel<Index1D, ArrayView<byte>, ArrayView<int>>(DivisorByDivisorKernels.PublishFirstHitKernel));
private Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, ArrayView<GpuUInt128>, GpuUInt128, GpuUInt128> GetCandidateGenerationKernel(Accelerator accelerator) =>
_candidateGenerationKernelCache.GetOrAdd(
accelerator,
@@ -137,6 +143,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
resources.DivisorsBuffer,
resources.ExponentBuffer,
resources.HitsBuffer,
resources.HitIndexBuffer,
resources.CandidateBuffer,
resources.NextStartBuffer,
resources.DivisorDeltaBuffer,
@@ -148,9 +155,9 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
resources.CandidateMaskKernel,
resources.CandidateCompactionKernel,
resources.CandidateGenerationKernel,
resources.HitDetectionKernel,
resources.Divisors,
resources.Exponents,
resources.Hits,
resources.DivisorData,
resources.CycleCandidates,
resources.CycleLengths,
@@ -210,6 +217,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
MemoryBuffer1D<MontgomeryDivisorData, Stride1D.Dense> divisorsBuffer,
MemoryBuffer1D<ulong, Stride1D.Dense> exponentBuffer,
MemoryBuffer1D<byte, Stride1D.Dense> hitsBuffer,
MemoryBuffer1D<int, Stride1D.Dense> hitIndexBuffer,
MemoryBuffer1D<ulong, Stride1D.Dense> candidateBuffer,
MemoryBuffer1D<GpuUInt128, Stride1D.Dense> nextStartBuffer,
MemoryBuffer1D<ulong, Stride1D.Dense> divisorDeltaBuffer,
@@ -221,9 +229,9 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
Action<Index1D, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, byte, ArrayView<byte>> candidateMaskKernel,
Action<KernelConfig, Index1D, ArrayView<byte>, ArrayView<ulong>, ArrayView<ulong>, ArrayView<int>> candidateCompactionKernel,
Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, ArrayView<GpuUInt128>, GpuUInt128, GpuUInt128> candidateGenerationKernel,
Action<Index1D, ArrayView<byte>, ArrayView<int>> hitDetectionKernel,
in ulong[] divisors,
ulong[] exponents,
byte[] hits,
MontgomeryDivisorData[] divisorData,
ulong[] cycleCandidates,
ulong[] cycleLengths,
@@ -282,7 +290,6 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
ulong[] filteredDivisors = ulongPool.Rent(chunkCapacity);
var viewCache = new BufferSliceCache(divisorDeltaBuffer, remainderDeltaBuffer, remainderBuffer, hitsBuffer, remainderStride);
Span<ulong> candidateStorage = cycleCandidates.AsSpan();
Span<byte> hitStorage = hits.AsSpan();
Span<ulong> filteredStorage = filteredDivisors.AsSpan();
Span<ulong> cycleLengthStorage = cycleLengths.AsSpan();
Span<MontgomeryDivisorData> divisorDataStorage = divisorData.AsSpan();
@@ -399,10 +406,10 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
Span<MontgomeryDivisorData> divisorDataSpan = divisorDataStorage[..admissibleCount];
Span<ulong> divisorSpan = divisorStorage[..admissibleCount];
Span<ulong> exponentSpan = exponentStorage[..admissibleCount];
Span<byte> hitsSpan = hitStorage[..admissibleCount];
ArrayView1D<MontgomeryDivisorData, Stride1D.Dense> divisorView = divisorsBuffer.View.SubView(0, admissibleCount);
ArrayView1D<ulong, Stride1D.Dense> exponentView = exponentBuffer.View.SubView(0, admissibleCount);
ArrayView1D<byte, Stride1D.Dense> hitsView = hitsBuffer.View.SubView(0, admissibleCount);
ArrayView1D<int, Stride1D.Dense> hitIndexView = hitIndexBuffer.View.SubView(0, 1);
for (int i = 0; i < admissibleCount; i++)
{
@@ -415,9 +422,8 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
divisorView.CopyFromCPU(ref MemoryMarshal.GetReference(divisorDataSpan), admissibleCount);
exponentView.CopyFromCPU(ref MemoryMarshal.GetReference(exponentSpan), admissibleCount);
kernel(admissibleCount, divisorView, exponentView, hitsView);
hitsView.CopyToCPU(ref MemoryMarshal.GetReference(hitsSpan), admissibleCount);
int hitIndex = System.MemoryExtensions.IndexOf(hitsSpan, (byte)1);
int hitIndex = FindFirstHitOnGpu(admissibleCount, hitsView, hitIndexView, hitDetectionKernel);
bool hitFound = hitIndex >= 0;
composite = hitFound;
int lastIndex = admissibleCount - 1;
@@ -601,6 +607,30 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
return filteredCount;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static int FindFirstHitOnGpu(
int count,
ArrayView1D<byte, Stride1D.Dense> hitsView,
ArrayView1D<int, Stride1D.Dense> hitIndexView,
Action<Index1D, ArrayView<byte>, ArrayView<int>> hitKernel)
{
// EvenPerfectBitScanner only calls this helper with positive counts,
// so the guard stays commented out to keep the hot path branch-free.
// if (count <= 0)
// {
// return -1;
// }
int sentinel = int.MaxValue;
hitIndexView.SubView(0, 1).CopyFromCPU(ref sentinel, 1);
hitKernel(count, hitsView, hitIndexView);
int firstHit = sentinel;
hitIndexView.SubView(0, 1).CopyToCPU(ref firstHit, 1);
return firstHit >= count ? -1 : firstHit;
}
private static byte FetchLastRemainder(ArrayView1D<byte, Stride1D.Dense> remainderView, int count)
{
// Callers guard against zero counts before invoking this helper to keep the hot path branch-free.
@@ -811,6 +841,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
DivisorsBuffer = accelerator.Allocate1D<MontgomeryDivisorData>(actualCapacity);
ExponentBuffer = accelerator.Allocate1D<ulong>(actualCapacity);
HitsBuffer = accelerator.Allocate1D<byte>(actualCapacity);
HitIndexBuffer = accelerator.Allocate1D<int>(1);
CandidateBuffer = accelerator.Allocate1D<ulong>(actualCapacity);
NextStartBuffer = accelerator.Allocate1D<GpuUInt128>(1);
DivisorDeltaBuffer = accelerator.Allocate1D<ulong>(actualCapacity);
@@ -820,7 +851,6 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
ArrayPool<ulong> ulongPool = ThreadStaticPools.UlongPool;
Divisors = ulongPool.Rent(actualCapacity);
Exponents = ulongPool.Rent(actualCapacity);
Hits = ThreadStaticPools.BytePool.Rent(actualCapacity);
DivisorData = ThreadStaticPools.MontgomeryDivisorDataPool.Rent(actualCapacity);
CycleCandidates = ulongPool.Rent(cycleCapacity);
CycleLengths = ulongPool.Rent(cycleCapacity);
@@ -829,6 +859,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
CandidateMaskKernel = owner.GetCandidateMaskKernel(accelerator);
CandidateCompactionKernel = owner.GetCandidateCompactionKernel(accelerator);
CandidateGenerationKernel = owner.GetCandidateGenerationKernel(accelerator);
HitDetectionKernel = owner.GetHitDetectionKernel(accelerator);
Capacity = actualCapacity;
CycleCapacity = cycleCapacity;
}
@@ -839,6 +870,8 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
internal readonly MemoryBuffer1D<byte, Stride1D.Dense> HitsBuffer;
internal readonly MemoryBuffer1D<int, Stride1D.Dense> HitIndexBuffer;
internal readonly MemoryBuffer1D<ulong, Stride1D.Dense> CandidateBuffer;
internal readonly MemoryBuffer1D<GpuUInt128, Stride1D.Dense> NextStartBuffer;
@@ -854,8 +887,6 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
internal readonly ulong[] Exponents;
internal readonly byte[] Hits;
internal readonly MontgomeryDivisorData[] DivisorData;
internal readonly ulong[] CycleCandidates;
@@ -868,6 +899,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
internal readonly Action<Index1D, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, byte, ArrayView<byte>> CandidateMaskKernel;
internal readonly Action<KernelConfig, Index1D, ArrayView<byte>, ArrayView<ulong>, ArrayView<ulong>, ArrayView<int>> CandidateCompactionKernel;
internal readonly Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, ArrayView<GpuUInt128>, GpuUInt128, GpuUInt128> CandidateGenerationKernel;
internal readonly Action<Index1D, ArrayView<byte>, ArrayView<int>> HitDetectionKernel;
internal readonly int Capacity;
@@ -878,6 +910,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
DivisorsBuffer.Dispose();
ExponentBuffer.Dispose();
HitsBuffer.Dispose();
HitIndexBuffer.Dispose();
CandidateBuffer.Dispose();
NextStartBuffer.Dispose();
DivisorDeltaBuffer.Dispose();
@@ -885,11 +918,9 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
RemainderBuffer.Dispose();
FilterCountBuffer.Dispose();
ArrayPool<ulong> ulongPool = ThreadStaticPools.UlongPool;
ArrayPool<byte> bytePool = ThreadStaticPools.BytePool;
ArrayPool<MontgomeryDivisorData> divisorPool = ThreadStaticPools.MontgomeryDivisorDataPool;
ulongPool.Return(Divisors, clearArray: false);
ulongPool.Return(Exponents, clearArray: false);
bytePool.Return(Hits, clearArray: false);
divisorPool.Return(DivisorData, clearArray: false);
ulongPool.Return(CycleCandidates, clearArray: false);
ulongPool.Return(CycleLengths, clearArray: false);