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Use GpuUInt128 in GPU divisor candidate generation

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Marek Lemańczyk committed 2025-10-22 06:05:22 +02:00
1 parent bfc5712d81
commit 4d8ea9dccd
2 files changed
+55 -66
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PerfectNumbers.Core/Gpu/Kernels/DivisorByDivisorKernels.cs
+40 -5
View File
@@ -17,7 +17,12 @@ internal static class DivisorByDivisorKernels
hits[index] = montgomeryResult == 1UL ? (byte)1 : (byte)0;
}
public static void GenerateCandidatesAndGapsKernel(Index1D index, ArrayView<ulong> candidates, ArrayView<ulong> gaps, ulong startValue, ulong stride)
public static void GenerateCandidatesAndGapsKernel(
Index1D index,
ArrayView<ulong> candidates,
ArrayView<ulong> gaps,
GpuUInt128 startValue,
GpuUInt128 stride)
{
int globalIndex = index;
int candidateLength = (int)candidates.Length;
@@ -27,14 +32,44 @@ internal static class DivisorByDivisorKernels
}
ulong offset = (ulong)globalIndex;
ulong candidate = startValue + offset * stride;
candidates[globalIndex] = candidate;
GpuUInt128 candidateValue;
if (offset == 0UL)
{
candidateValue = startValue;
}
else
{
candidateValue = stride;
candidateValue.Mul(offset);
candidateValue.Add(startValue);
}
candidates[globalIndex] = candidateValue.Low;
int gapLength = (int)gaps.Length;
if (globalIndex < gapLength)
if (globalIndex >= gapLength)
{
gaps[globalIndex] = offset == 0UL ? 0UL : stride;
return;
}
if (offset == 0UL)
{
gaps[globalIndex] = 0UL;
return;
}
GpuUInt128 previousValue = startValue;
ulong previousOffset = offset - 1UL;
if (previousOffset != 0UL)
{
GpuUInt128 scaledStride = stride;
scaledStride.Mul(previousOffset);
previousValue.Add(scaledStride);
}
GpuUInt128 gapValue = candidateValue;
gapValue.Sub(previousValue);
gaps[globalIndex] = gapValue.Low;
}
public static void ComputeRemainderDeltasKernel(Index1D index, ArrayView<ulong> gaps, ArrayView<byte> deltas, byte modulus)
PerfectNumbers.Core/Gpu/MersenneNumberDivisorByDivisorGpuTester.cs
+15 -61
View File
@@ -28,7 +28,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
private readonly ConcurrentDictionary<Accelerator, Action<Index1D, ArrayView<ulong>, ArrayView<byte>, byte>> _remainderDeltaKernelCache = new(AcceleratorReferenceComparer.Instance);
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<Index1D, ArrayView<ulong>, ArrayView<ulong>, ulong, ulong>> _candidateGenerationKernelCache = new(AcceleratorReferenceComparer.Instance);
private readonly ConcurrentDictionary<Accelerator, Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, GpuUInt128, GpuUInt128>> _candidateGenerationKernelCache = new(AcceleratorReferenceComparer.Instance);
private readonly ConcurrentDictionary<Accelerator, ConcurrentBag<BatchResources>> _resourcePools = new(AcceleratorReferenceComparer.Instance);
private readonly ConcurrentBag<GpuContextPool.GpuContextLease> _acceleratorPool = new();
private readonly ConcurrentBag<DivisorScanSession> _sessionPool = new();
@@ -52,10 +52,10 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
accelerator,
acc => acc.LoadAutoGroupedStreamKernel<Index1D, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, byte, ArrayView<byte>>(DivisorByDivisorKernels.EvaluateCandidateMaskKernel));
private Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, ulong, ulong> GetCandidateGenerationKernel(Accelerator accelerator) =>
private Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, GpuUInt128, GpuUInt128> GetCandidateGenerationKernel(Accelerator accelerator) =>
_candidateGenerationKernelCache.GetOrAdd(
accelerator,
acc => acc.LoadAutoGroupedStreamKernel<Index1D, ArrayView<ulong>, ArrayView<ulong>, ulong, ulong>(DivisorByDivisorKernels.GenerateCandidatesAndGapsKernel));
acc => acc.LoadAutoGroupedStreamKernel<Index1D, ArrayView<ulong>, ArrayView<ulong>, GpuUInt128, GpuUInt128>(DivisorByDivisorKernels.GenerateCandidatesAndGapsKernel));
public int GpuBatchSize
{
@@ -208,7 +208,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
Action<Index1D, ArrayView<ulong>, ArrayView<byte>, byte> remainderDeltaKernel,
Action<KernelConfig, Index1D, ArrayView<byte>, ArrayView<byte>, byte, byte> remainderScanKernel,
Action<Index1D, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, byte, ArrayView<byte>> candidateMaskKernel,
Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, ulong, ulong> candidateGenerationKernel,
Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, GpuUInt128, GpuUInt128> candidateGenerationKernel,
in ulong[] divisors,
ulong[] exponents,
byte[] hits,
@@ -268,7 +268,6 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
ArrayPool<ulong> ulongPool = ThreadStaticPools.UlongPool;
ulong[] filteredDivisors = ulongPool.Rent(chunkCapacity);
ulong[]? fallbackDivisorGaps = null;
var viewCache = new BufferSliceCache(divisorDeltaBuffer, remainderDeltaBuffer, remainderBuffer, hitsBuffer, remainderStride);
Span<ulong> candidateStorage = cycleCandidates.AsSpan();
Span<byte> hitStorage = hits.AsSpan();
@@ -306,58 +305,17 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
UInt128 localDivisor = currentDivisor128;
UInt128 nextDivisor;
bool strideFits = twoP128 <= (UInt128)ulong.MaxValue;
bool baseFits = localDivisor <= (UInt128)ulong.MaxValue;
bool useGpuGeneration = strideFits && baseFits;
if (useGpuGeneration)
ArrayView1D<ulong, Stride1D.Dense> candidateView = candidateBuffer.View.SubView(0, effectiveCount);
GpuUInt128 gpuStartValue = new GpuUInt128(localDivisor);
GpuUInt128 gpuStride = new GpuUInt128(twoP128);
GenerateCandidatesOnGpu(effectiveCount, gpuStartValue, gpuStride, candidateView, gapView, candidateGenerationKernel);
if (effectiveCount > 0)
{
ulong startValue = (ulong)localDivisor;
ulong stride = (ulong)twoP128;
ArrayView1D<ulong, Stride1D.Dense> candidateView = candidateBuffer.View.SubView(0, effectiveCount);
GenerateCandidatesOnGpu(effectiveCount, startValue, stride, candidateView, gapView, candidateGenerationKernel);
if (effectiveCount > 0)
{
candidateView.CopyToCPU(ref MemoryMarshal.GetReference(candidateSpan), effectiveCount);
}
nextDivisor = localDivisor + twoP128 * (UInt128)(ulong)effectiveCount;
candidateView.CopyToCPU(ref MemoryMarshal.GetReference(candidateSpan), effectiveCount);
}
else
{
if (fallbackDivisorGaps is null || fallbackDivisorGaps.Length < chunkCapacity)
{
if (fallbackDivisorGaps is not null)
{
ulongPool.Return(fallbackDivisorGaps, clearArray: false);
}
fallbackDivisorGaps = ulongPool.Rent(chunkCapacity);
}
Span<ulong> gapSpan = fallbackDivisorGaps.AsSpan(0, effectiveCount);
UInt128 cursor = localDivisor;
for (int i = 0; i < effectiveCount; i++)
{
ulong divisorValue = (ulong)cursor;
candidateSpan[i] = divisorValue;
cursor += twoP128;
}
if (effectiveCount > 0)
{
gapSpan[0] = 0UL;
for (int i = 1; i < effectiveCount; i++)
{
gapSpan[i] = candidateSpan[i] - candidateSpan[i - 1];
}
gapView.CopyFromCPU(ref MemoryMarshal.GetReference(gapSpan), effectiveCount);
}
nextDivisor = cursor;
}
nextDivisor = localDivisor + twoP128 * (UInt128)effectiveCount;
processedCount += (ulong)effectiveCount;
if (effectiveCount > 0)
@@ -447,10 +405,6 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
}
ulongPool.Return(filteredDivisors, clearArray: false);
if (fallbackDivisorGaps is not null)
{
ulongPool.Return(fallbackDivisorGaps, clearArray: false);
}
coveredRange = composite || processedAll || (currentDivisor128 > allowedMax128);
return composite;
@@ -530,11 +484,11 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static void GenerateCandidatesOnGpu(
int count,
ulong startValue,
ulong stride,
GpuUInt128 startValue,
GpuUInt128 stride,
ArrayView1D<ulong, Stride1D.Dense> candidateView,
ArrayView1D<ulong, Stride1D.Dense> gapView,
Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, ulong, ulong> kernel)
Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, GpuUInt128, GpuUInt128> kernel)
{
if (count <= 0)
{
@@ -854,7 +808,7 @@ public sealed class MersenneNumberDivisorByDivisorGpuTester : IMersenneNumberDiv
internal readonly Action<KernelConfig, Index1D, ArrayView<byte>, ArrayView<byte>, byte, byte> RemainderScanKernel;
internal readonly Action<Index1D, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, ArrayView<byte>, byte, ArrayView<byte>> CandidateMaskKernel;
internal readonly Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, ulong, ulong> CandidateGenerationKernel;
internal readonly Action<Index1D, ArrayView<ulong>, ArrayView<ulong>, GpuUInt128, GpuUInt128> CandidateGenerationKernel;
internal readonly int Capacity;