Files
even-perfect-numbers-scanner/PerfectNumbers.Core/Gpu/GpuKernelPool.cs
T

865 lines
34 KiB
C#
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
using System.Collections.Concurrent;
using System.Runtime.CompilerServices;
using ILGPU;
using ILGPU.Runtime;
using static PerfectNumbers.Core.Gpu.GpuContextPool;
namespace PerfectNumbers.Core.Gpu;
public readonly struct ResidueAutomatonArgs
{
public readonly ulong Q0M10;
public readonly ulong Step10;
public readonly ulong Q0M8;
public readonly ulong Step8;
public readonly ulong Q0M3;
public readonly ulong Step3;
public readonly ulong Q0M5;
public readonly ulong Step5;
public ResidueAutomatonArgs(ulong q0m10, ulong step10, ulong q0m8, ulong step8, ulong q0m3, ulong step3, ulong q0m5, ulong step5)
{
Q0M10 = q0m10; Step10 = step10; Q0M8 = q0m8; Step8 = step8; Q0M3 = q0m3; Step3 = step3; Q0M5 = q0m5; Step5 = step5;
}
}
public sealed class KernelContainer
{
// Serializes first-time initialization of kernels/buffers per accelerator.
public Action<AcceleratorStream, Index1D, ulong, ulong, ArrayView<GpuUInt128>, ArrayView<ulong>>? Order;
public Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong,
ulong, ulong, ulong, ulong, ArrayView<ulong>, ArrayView1D<ulong, Stride1D.Dense>>? Incremental;
public Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong,
ResidueAutomatonArgs, ArrayView<ulong>, ArrayView1D<ulong, Stride1D.Dense>,
ArrayView1D<uint, Stride1D.Dense>, ArrayView1D<uint, Stride1D.Dense>,
ArrayView1D<ulong, Stride1D.Dense>, ArrayView1D<ulong, Stride1D.Dense>>? Pow2Mod;
public Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong,
ResidueAutomatonArgs, ArrayView<int>, ArrayView1D<ulong, Stride1D.Dense>>? IncrementalOrder;
public Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong,
ResidueAutomatonArgs, ArrayView<int>, ArrayView1D<ulong, Stride1D.Dense>>? Pow2ModOrder;
public Action<AcceleratorStream, Index1D, ArrayView1D<MontgomeryDivisorData, Stride1D.Dense>, ArrayView1D<int, Stride1D.Dense>, ArrayView1D<ulong, Stride1D.Dense>, int>? MontgomeryOddPowers;
// Optional device buffer with small divisor cycles (<= 4M). Index = divisor, value = cycle length.
public MemoryBuffer1D<ulong, Stride1D.Dense>? SmallCycles;
public MemoryBuffer1D<uint, Stride1D.Dense>? SmallPrimesLastOne;
public MemoryBuffer1D<ulong, Stride1D.Dense>? SmallPrimesPow2LastOne;
public MemoryBuffer1D<uint, Stride1D.Dense>? SmallPrimesLastSeven;
public MemoryBuffer1D<ulong, Stride1D.Dense>? SmallPrimesPow2LastSeven;
public static T InitOnce<T>(ref T? slot, Func<T> factory) where T : class
{
var current = Volatile.Read(ref slot);
if (current is not null)
{
return current;
}
current = Volatile.Read(ref slot);
if (current is null)
{
current = factory();
Volatile.Write(ref slot, current);
}
return current;
}
}
public readonly struct ResiduePrimeViews(
ArrayView1D<uint, Stride1D.Dense> lastOne,
ArrayView1D<uint, Stride1D.Dense> lastSeven,
ArrayView1D<ulong, Stride1D.Dense> lastOnePow2,
ArrayView1D<ulong, Stride1D.Dense> lastSevenPow2)
{
public readonly ArrayView1D<uint, Stride1D.Dense> LastOne = lastOne;
public readonly ArrayView1D<uint, Stride1D.Dense> LastSeven = lastSeven;
public readonly ArrayView1D<ulong, Stride1D.Dense> LastOnePow2 = lastOnePow2;
public readonly ArrayView1D<ulong, Stride1D.Dense> LastSevenPow2 = lastSevenPow2;
}
public ref struct GpuKernelLease(IDisposable limiter, GpuContextLease gpu, KernelContainer kernels)
{
private bool disposedValue;
private IDisposable? _limiter = limiter;
private GpuContextLease? _gpu = gpu;
private KernelContainer _kernels = kernels;
private AcceleratorStream? _stream;
private object? _executionLock = gpu.ExecutionLock;
public readonly Accelerator Accelerator => _gpu?.Accelerator ?? throw new NullReferenceException("GPU context is already released");
public AcceleratorStream Stream
{
get
{
if (_stream is { } stream)
{
return stream;
}
// It feels that we can combine these into 1 return statement, but that increases the max stack frame size to 3 from 2
stream = Accelerator.CreateStream();
_stream = stream;
return stream;
}
}
public readonly ExecutionScope EnterExecutionScope() => new ExecutionScope(_executionLock);
public readonly Action<AcceleratorStream, Index1D, ulong, ulong, ArrayView<GpuUInt128>, ArrayView<ulong>> OrderKernel
{
get
{
var accel = Accelerator; // avoid capturing 'this' in lambda
lock (_gpu!.Value.KernelInitLock)
{
return KernelContainer.InitOnce(ref _kernels.Order, () =>
{
var loaded = accel.LoadAutoGroupedStreamKernel<Index1D, ulong, ulong, ArrayView<GpuUInt128>, ArrayView<ulong>>(OrderKernelScan);
var kernel = KernelUtil.GetKernel(loaded);
return kernel.CreateLauncherDelegate<Action<AcceleratorStream, Index1D, ulong, ulong, ArrayView<GpuUInt128>, ArrayView<ulong>>>();
});
}
}
}
public readonly Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ResidueAutomatonArgs, ArrayView<ulong>, ArrayView1D<ulong, Stride1D.Dense>, ArrayView1D<uint, Stride1D.Dense>, ArrayView1D<uint, Stride1D.Dense>, ArrayView1D<ulong, Stride1D.Dense>, ArrayView1D<ulong, Stride1D.Dense>> Pow2ModKernel
{
get
{
var accel = Accelerator;
lock (_gpu!.Value.KernelInitLock)
{
return KernelContainer.InitOnce(ref _kernels.Pow2Mod, () =>
{
var loaded = accel.LoadAutoGroupedStreamKernel<Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ResidueAutomatonArgs, ArrayView<ulong>, ArrayView1D<ulong, Stride1D.Dense>, ArrayView1D<uint, Stride1D.Dense>, ArrayView1D<uint, Stride1D.Dense>, ArrayView1D<ulong, Stride1D.Dense>, ArrayView1D<ulong, Stride1D.Dense>>(Pow2ModKernelScan);
var kernel = KernelUtil.GetKernel(loaded);
return kernel.CreateLauncherDelegate<Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ResidueAutomatonArgs, ArrayView<ulong>, ArrayView1D<ulong, Stride1D.Dense>, ArrayView1D<uint, Stride1D.Dense>, ArrayView1D<uint, Stride1D.Dense>, ArrayView1D<ulong, Stride1D.Dense>, ArrayView1D<ulong, Stride1D.Dense>>>();
});
}
}
}
public readonly Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ulong, ulong, ulong, ulong, ArrayView<ulong>, ArrayView1D<ulong, Stride1D.Dense>> IncrementalKernel
{
get
{
var accel = Accelerator;
lock (_gpu!.Value.KernelInitLock)
{
return KernelContainer.InitOnce(ref _kernels.Incremental, () =>
{
var loaded = accel.LoadAutoGroupedStreamKernel<Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ulong, ulong, ulong, ulong, ArrayView<ulong>, ArrayView1D<ulong, Stride1D.Dense>>(IncrementalKernelScan);
var kernel = KernelUtil.GetKernel(loaded);
return kernel.CreateLauncherDelegate<Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ulong, ulong, ulong, ulong, ArrayView<ulong>, ArrayView1D<ulong, Stride1D.Dense>>>();
});
}
}
}
public readonly Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ResidueAutomatonArgs, ArrayView<int>, ArrayView1D<ulong, Stride1D.Dense>> IncrementalOrderKernel
{
get
{
var accel = Accelerator;
lock (_gpu!.Value.KernelInitLock)
{
return KernelContainer.InitOnce(ref _kernels.IncrementalOrder, () =>
{
var loaded = accel.LoadAutoGroupedStreamKernel<Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ResidueAutomatonArgs, ArrayView<int>, ArrayView1D<ulong, Stride1D.Dense>>(IncrementalOrderKernelScan);
var kernel = KernelUtil.GetKernel(loaded);
return kernel.CreateLauncherDelegate<Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ResidueAutomatonArgs, ArrayView<int>, ArrayView1D<ulong, Stride1D.Dense>>>();
});
}
}
}
public readonly Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ResidueAutomatonArgs, ArrayView<int>, ArrayView1D<ulong, Stride1D.Dense>> Pow2ModOrderKernel
{
get
{
var accel = Accelerator;
lock (_gpu!.Value.KernelInitLock)
{
return KernelContainer.InitOnce(ref _kernels.Pow2ModOrder, () =>
{
var loaded = accel.LoadAutoGroupedStreamKernel<Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ResidueAutomatonArgs, ArrayView<int>, ArrayView1D<ulong, Stride1D.Dense>>(Pow2ModOrderKernelScan);
var kernel = KernelUtil.GetKernel(loaded);
return kernel.CreateLauncherDelegate<Action<AcceleratorStream, Index1D, ulong, GpuUInt128, GpuUInt128, byte, ulong, ResidueAutomatonArgs, ArrayView<int>, ArrayView1D<ulong, Stride1D.Dense>>>();
});
}
}
}
public readonly Action<AcceleratorStream, Index1D, ArrayView1D<MontgomeryDivisorData, Stride1D.Dense>, ArrayView1D<int, Stride1D.Dense>, ArrayView1D<ulong, Stride1D.Dense>, int> MontgomeryOddPowerKernel
{
get
{
var accel = Accelerator;
lock (_gpu!.Value.KernelInitLock)
{
return KernelContainer.InitOnce(ref _kernels.MontgomeryOddPowers, () =>
{
var loaded = accel.LoadAutoGroupedStreamKernel<Index1D, ArrayView1D<MontgomeryDivisorData, Stride1D.Dense>, ArrayView1D<int, Stride1D.Dense>, ArrayView1D<ulong, Stride1D.Dense>, int>(MontgomeryOddPowerKernelScan);
var kernel = KernelUtil.GetKernel(loaded);
return kernel.CreateLauncherDelegate<Action<AcceleratorStream, Index1D, ArrayView1D<MontgomeryDivisorData, Stride1D.Dense>, ArrayView1D<int, Stride1D.Dense>, ArrayView1D<ulong, Stride1D.Dense>, int>>();
});
}
}
}
private static void MontgomeryOddPowerKernelScan(
Index1D index,
ArrayView1D<MontgomeryDivisorData, Stride1D.Dense> divisors,
ArrayView1D<int, Stride1D.Dense> counts,
ArrayView1D<ulong, Stride1D.Dense> results,
int stride)
{
int tableIndex = index.X;
int baseOffset = tableIndex * stride;
MontgomeryDivisorData divisor = divisors[tableIndex];
int oddPowerCount = counts[tableIndex];
if (oddPowerCount <= 0)
{
return;
}
ulong montgomeryTwo = divisor.MontgomeryTwo;
results[baseOffset] = montgomeryTwo;
if (oddPowerCount == 1)
{
return;
}
ulong modulus = divisor.Modulus;
ulong nPrime = divisor.NPrime;
ulong square = divisor.MontgomeryTwoSquared;
ulong current = montgomeryTwo;
for (int i = 1; i < oddPowerCount; i++)
{
current = ULongExtensions.MontgomeryMultiply(current, square, modulus, nPrime);
results[baseOffset + i] = current;
}
}
// TODO: Plumb the small-cycles device buffer into all kernels that can benefit
// (some already accept it). Consider a compact type (byte/ushort) for memory footprint.
private static void IncrementalKernelScan(Index1D index, ulong exponent, GpuUInt128 twoP, GpuUInt128 kStart, byte lastIsSeven, ulong divMul,
ulong q0m10, ulong q0m8, ulong q0m3, ulong q0m5, ArrayView<ulong> orders,
ArrayView1D<ulong, Stride1D.Dense> smallCycles)
{
ulong idx = (ulong)index.X;
// TODO: Replace these `%` computations with the precomputed Mod3/Mod5 tables so GPU kernels reuse cached residues
// instead of performing modulo operations that the benchmarks showed slower on wide sweeps.
ulong idxMod3 = idx % 3UL;
ulong idxMod5 = idx % 5UL;
// residue automaton
ulong step10 = (exponent.Mod10() << 1).Mod10();
ulong r10 = q0m10 + (step10 * idx).Mod10();
r10 -= (r10 >= 10UL) ? 10UL : 0UL;
bool shouldCheck = r10 != 5UL; // skip q ≡ 5 (mod 10); other residues handled by r8/r3/r5
if (shouldCheck)
{
ulong step8 = ((exponent & 7UL) << 1) & 7UL;
ulong r8 = (q0m8 + ((step8 * idx) & 7UL)) & 7UL;
if (r8 != 1UL && r8 != 7UL)
{
shouldCheck = false;
}
else
{
// TODO: Swap these `%` filters to the shared Mod helpers so the residue automaton matches the benchmarked
// bitmask-based implementation for GPU workloads.
ulong step3 = ((exponent % 3UL) << 1) % 3UL;
ulong r3 = q0m3 + (step3 * idxMod3); r3 -= (r3 >= 3UL) ? 3UL : 0UL;
if (r3 == 0UL)
{
shouldCheck = false;
}
else
{
ulong step5Loc = ((exponent % 5UL) << 1) % 5UL;
ulong r5 = q0m5 + (step5Loc * idxMod5); if (r5 >= 5UL) r5 -= 5UL;
if (r5 == 0UL)
{
shouldCheck = false;
}
}
}
}
if (!shouldCheck)
{
orders[index] = 0UL;
return;
}
// TODO: Is this expected that the value of kStart is modified?
GpuUInt128 k = kStart + (GpuUInt128)idx;
GpuUInt128 q = twoP;
q.Mul64(k);
q.Add(GpuUInt128.One);
ReadOnlyGpuUInt128 readOnlyQ = q.AsReadOnly();
// Small-cycles in-kernel early rejection from device table
if (q.High == 0UL && q.Low < (ulong)smallCycles.Length)
{
ulong cycle = smallCycles[(int)q.Low];
if (cycle != 0UL && cycle <= exponent && (exponent % cycle) != 0UL)
{
orders[index] = 0UL;
return;
}
}
// TODO: q will be lowered by GpuUInt128.One here. Is this expected? Maybe that's why we have issues with the incremental kernel? Review other places where we use GpuUInt128 operators.
GpuUInt128 phi = q - GpuUInt128.One;
// TODO: Do we have the check here because we don't support high values or this is expected result?
if (phi.High != 0UL)
{
orders[index] = 0UL;
return;
}
ulong phi64 = phi.Low;
// TODO: Replace these Pow2Mod calls with the ProcessEightBitWindows helper when the shared windowed
// scalar implementation lands; benchmarks showed the windowed kernel trimming per-divisor runtime by ~2.4×.
if (GpuUInt128.Pow2Mod(phi64, in readOnlyQ) != GpuUInt128.One)
{
orders[index] = 0UL;
return;
}
GpuUInt128 halfPow = GpuUInt128.Pow2Mod(phi64 >> 1, in readOnlyQ) - GpuUInt128.One;
if (GpuUInt128.BinaryGcd(halfPow, q) != GpuUInt128.One)
{
orders[index] = 0UL;
return;
}
ulong div = FastDiv64Gpu(phi64, exponent, divMul);
GpuUInt128 divPow = GpuUInt128.Pow2Mod(div, in readOnlyQ) - GpuUInt128.One;
if (GpuUInt128.BinaryGcd(divPow, q) != GpuUInt128.One)
{
orders[index] = 0UL;
return;
}
orders[index] = 1UL;
}
private static void OrderKernelScan(Index1D index, ulong exponent, ulong divMul, ArrayView<GpuUInt128> qs, ArrayView<ulong> orders)
{
GpuUInt128 q = qs[index];
ReadOnlyGpuUInt128 readOnlyQ = q.AsReadOnly();
GpuUInt128 phi = q - GpuUInt128.One;
if (phi.High != 0UL)
{
orders[index] = 0UL;
return;
}
ulong phi64 = phi.Low;
// TODO: Once the ProcessEightBitWindows helper is available, switch this order kernel to that faster
// Pow2Mod variant so cycle checks inherit the same gains observed in GpuPow2ModBenchmarks.
GpuUInt128 pow = GpuUInt128.Pow2Mod(phi64, in readOnlyQ);
if (pow != GpuUInt128.One)
{
orders[index] = 0UL;
return;
}
GpuUInt128 halfPow = GpuUInt128.Pow2Mod(phi64 >> 1, in readOnlyQ) - GpuUInt128.One;
if (GpuUInt128.BinaryGcd(halfPow, q) != GpuUInt128.One)
{
orders[index] = 0UL;
return;
}
ulong div = FastDiv64Gpu(phi64, exponent, divMul);
GpuUInt128 divPow = GpuUInt128.Pow2Mod(div, in readOnlyQ) - GpuUInt128.One;
if (GpuUInt128.BinaryGcd(divPow, q) != GpuUInt128.One)
{
orders[index] = 0UL;
return;
}
orders[index] = exponent;
}
private void Dispose(bool disposing)
{
if (!disposedValue)
{
if (disposing)
{
_stream?.Dispose();
_stream = null;
if (_gpu.HasValue)
{
_gpu.Value.ReturnToPool();
}
_gpu = null;
_executionLock = null;
_limiter?.Dispose();
_limiter = null;
}
// free unmanaged resources (unmanaged objects) and override finalizer
// set large fields to null
disposedValue = true;
}
}
private static void Pow2ModKernelScan(Index1D index, ulong exponent, GpuUInt128 twoP, GpuUInt128 kStart, byte lastIsSeven, ulong _,
ResidueAutomatonArgs ra, ArrayView<ulong> orders,
ArrayView1D<ulong, Stride1D.Dense> smallCycles,
ArrayView1D<uint, Stride1D.Dense> smallPrimesLastOne,
ArrayView1D<uint, Stride1D.Dense> smallPrimesLastSeven,
ArrayView1D<ulong, Stride1D.Dense> smallPrimesPow2LastOne,
ArrayView1D<ulong, Stride1D.Dense> smallPrimesPow2LastSeven)
{
ulong idx = (ulong)index.X;
ulong idxMod3 = idx % 3UL;
ulong idxMod5 = idx % 5UL;
ulong r10 = ra.Q0M10 + (ra.Step10 * idx).Mod10(); r10 -= (r10 >= 10UL) ? 10UL : 0UL;
bool shouldCheck = r10 != 5UL;
if (shouldCheck)
{
ulong r8 = (ra.Q0M8 + ((ra.Step8 * idx) & 7UL)) & 7UL;
if (r8 != 1UL && r8 != 7UL)
{
shouldCheck = false;
}
else
{
ulong r3 = ra.Q0M3 + (ra.Step3 * idxMod3);
if (r3 >= 6UL) r3 -= 6UL;
if (r3 >= 3UL) r3 -= 3UL;
if (r3 == 0UL)
{
shouldCheck = false;
}
else
{
ulong r5 = ra.Q0M5 + (ra.Step5 * idxMod5);
if (r5 >= 15UL) r5 -= 15UL;
if (r5 >= 10UL) r5 -= 10UL;
if (r5 >= 5UL) r5 -= 5UL;
if (r5 == 0UL)
{
shouldCheck = false;
}
}
}
}
if (!shouldCheck)
{
orders[index] = 0UL;
return;
}
// TODO: kStart is modified after this. Is this expected?
kStart.Add(idx);
GpuUInt128 q = twoP;
q.Mul64(kStart);
q.Add(GpuUInt128.One);
ReadOnlyGpuUInt128 readOnlyQ = q.AsReadOnly();
if (q.High == 0UL && q.Low < (ulong)smallCycles.Length)
{
ulong cycle = smallCycles[(int)q.Low];
// cycle should always be initialized if we're within array limit in production code
if (cycle != 0UL && cycle <= exponent && (exponent % cycle) != 0UL)
{
orders[index] = 0UL;
return;
}
}
// TODO: Swap Pow2Minus1Mod for the eight-bit window helper once the scalar version switches;
// benchmarks show the windowed variant cuts large-divisor scans from ~51 µs to ~21 µs.
if (GpuUInt128.Pow2Minus1Mod(exponent, in readOnlyQ) != GpuUInt128.Zero)
{
orders[index] = 0UL;
return;
}
ArrayView1D<uint, Stride1D.Dense> primes = lastIsSeven != 0 ? smallPrimesLastSeven : smallPrimesLastOne;
ArrayView1D<ulong, Stride1D.Dense> primesPow2 = lastIsSeven != 0 ? smallPrimesPow2LastSeven : smallPrimesPow2LastOne;
int primesLen = (int)primes.Length;
for (int i = 0; i < primesLen; i++)
{
ulong square = primesPow2[i];
if (new GpuUInt128(0UL, square) > q)
{
break;
}
ulong prime = primes[i];
if (Mod128By64(q, prime) == 0UL)
{
orders[index] = 0UL;
return;
}
}
orders[index] = exponent;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static ulong FastDiv64Gpu(ulong value, ulong divisor, ulong mul)
{
ulong quotient = GpuUInt128.MulHigh(value, mul);
GpuUInt128 remainder = new(0UL, value);
GpuUInt128 product = new(GpuUInt128.MulHigh(quotient, divisor), quotient * divisor);
remainder.Sub(product);
if (remainder.High != 0UL || remainder.Low >= divisor)
{
quotient++;
}
return quotient;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static ulong Mod128By64(GpuUInt128 value, ulong modulus)
{
ulong rem = 0UL;
ulong part = value.High;
for (int i = 0; i < 64; i++)
{
rem = (rem << 1) | (part >> 63);
if (rem >= modulus)
{
rem -= modulus;
}
part <<= 1;
}
part = value.Low;
for (int i = 0; i < 64; i++)
{
rem = (rem << 1) | (part >> 63);
if (rem >= modulus)
{
rem -= modulus;
}
part <<= 1;
}
return rem;
}
// Device-friendly small cycle length for 2 mod divisor
private static ulong CalculateCycleLengthSmall(ulong divisor)
{
if ((divisor & (divisor - 1UL)) == 0UL)
return 1UL;
ulong order = 1UL, pow = 2UL;
while (pow != 1UL)
{
pow <<= 1;
if (pow > divisor)
pow -= divisor;
order++;
}
return order;
}
private static void IncrementalOrderKernelScan(Index1D index, ulong exponent, GpuUInt128 twoP, GpuUInt128 kStart, byte lastIsSeven, ulong divMul,
ResidueAutomatonArgs ra, ArrayView<int> found, ArrayView1D<ulong, Stride1D.Dense> smallCycles)
{
ulong idx = (ulong)index.X;
ulong idxMod3 = idx % 3UL;
ulong idxMod5 = idx % 5UL;
ulong r10 = ra.Q0M10 + (ra.Step10 * idx).Mod10(); r10 -= (r10 >= 10UL) ? 10UL : 0UL;
bool shouldCheck = r10 != 5UL;
if (shouldCheck)
{
ulong r8 = (ra.Q0M8 + ((ra.Step8 * idx) & 7UL)) & 7UL;
if (r8 != 1UL && r8 != 7UL)
{
shouldCheck = false;
}
else
{
ulong r3 = ra.Q0M3 + (ra.Step3 * idxMod3);
if (r3 >= 6UL) r3 -= 6UL;
if (r3 >= 3UL) r3 -= 3UL;
if (r3 == 0UL)
{
shouldCheck = false;
}
else
{
ulong r5 = ra.Q0M5 + (ra.Step5 * idxMod5);
if (r5 >= 15UL) r5 -= 15UL;
if (r5 >= 10UL) r5 -= 10UL;
if (r5 >= 5UL) r5 -= 5UL;
if (r5 == 0UL)
{
shouldCheck = false;
}
}
}
}
if (!shouldCheck)
{
return;
}
GpuUInt128 k = kStart + (GpuUInt128)idx;
GpuUInt128 q = twoP;
q.Mul64(k);
q.Add(GpuUInt128.One);
ReadOnlyGpuUInt128 readOnlyQ = q.AsReadOnly();
// Small-cycles in-kernel early rejection from device table
if (q.High == 0UL && q.Low < (ulong)smallCycles.Length)
{
ulong cycle = smallCycles[(int)q.Low];
if (cycle != 0UL && cycle <= exponent && (exponent % cycle) != 0UL)
{
return;
}
}
GpuUInt128 phi = q - GpuUInt128.One;
if (phi.High != 0UL)
{
return;
}
ulong phi64 = phi.Low;
// TODO: Upgrade this pow2mod order kernel to the ProcessEightBitWindows helper once available so GPU residue
// scans avoid the single-bit ladder that benchmarks found to be 2.3× slower on large exponents.
if (GpuUInt128.Pow2Mod(phi64, in readOnlyQ) != GpuUInt128.One)
{
return;
}
GpuUInt128 halfPow = GpuUInt128.Pow2Mod(phi64 >> 1, in readOnlyQ) - GpuUInt128.One;
if (GpuUInt128.BinaryGcd(halfPow, q) != GpuUInt128.One)
{
return;
}
ulong div = FastDiv64Gpu(phi64, exponent, divMul);
GpuUInt128 divPow = GpuUInt128.Pow2Mod(div, in readOnlyQ) - GpuUInt128.One;
if (GpuUInt128.BinaryGcd(divPow, q) != GpuUInt128.One)
{
return;
}
Atomic.Or(ref found[0], 1);
}
private static void Pow2ModOrderKernelScan(Index1D index, ulong exponent, GpuUInt128 twoP, GpuUInt128 kStart, byte lastIsSeven, ulong _,
ResidueAutomatonArgs ra, ArrayView<int> found, ArrayView1D<ulong, Stride1D.Dense> smallCycles)
{
ulong idx = (ulong)index.X;
ulong idxMod3 = idx % 3UL;
ulong idxMod5 = idx % 5UL;
ulong r10 = ra.Q0M10 + (ra.Step10 * idx).Mod10(); r10 -= (r10 >= 10UL) ? 10UL : 0UL;
bool shouldCheck = r10 != 5UL;
if (shouldCheck)
{
ulong r8 = (ra.Q0M8 + ((ra.Step8 * idx) & 7UL)) & 7UL;
if (r8 != 1UL && r8 != 7UL)
{
shouldCheck = false;
}
else
{
ulong r3 = ra.Q0M3 + (ra.Step3 * idxMod3);
if (r3 >= 6UL) r3 -= 6UL;
if (r3 >= 3UL) r3 -= 3UL;
if (r3 == 0UL)
{
shouldCheck = false;
}
else
{
ulong r5 = ra.Q0M5 + (ra.Step5 * idxMod5);
if (r5 >= 15UL) r5 -= 15UL;
if (r5 >= 10UL) r5 -= 10UL;
if (r5 >= 5UL) r5 -= 5UL;
if (r5 == 0UL)
{
shouldCheck = false;
}
}
}
}
if (!shouldCheck)
{
return;
}
GpuUInt128 k = kStart + (GpuUInt128)idx;
GpuUInt128 q = twoP;
q.Mul64(k);
q.Add(GpuUInt128.One);
ReadOnlyGpuUInt128 readOnlyQ = q.AsReadOnly();
// Small-cycles in-kernel early rejection from device table
if (q.High == 0UL && q.Low < (ulong)smallCycles.Length)
{
ulong cycle = smallCycles[(int)q.Low];
if (cycle != 0UL && cycle <= exponent && (exponent % cycle) != 0UL)
{
return;
}
}
// TODO: Replace this Pow2Mod check with the ProcessEightBitWindows helper once Pow2Minus1Mod adopts it;
// residue order scans will then benefit from the same 2× speedup the benchmarked windowed kernel delivered.
if (GpuUInt128.Pow2Mod(exponent, in readOnlyQ) != GpuUInt128.One)
{
return;
}
Atomic.Or(ref found[0], 1);
}
public void Dispose()
{
// Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
Dispose(disposing: true);
// Enabled this when the struct is converted to a class
// GC.SuppressFinalize(this);
}
public readonly struct ExecutionScope
{
private readonly object? _lock;
public ExecutionScope(object? sync)
{
_lock = sync;
if (_lock is not null)
{
Monitor.Enter(_lock);
}
}
public void Dispose()
{
if (_lock is not null)
{
Monitor.Exit(_lock);
}
}
}
}
public class GpuKernelPool
{
private static readonly ConcurrentDictionary<Accelerator, KernelContainer> KernelCache = new(); // TODO: Replace this concurrent map with a simple accelerator-indexed lookup once kernel launchers are prewarmed during startup so we can drop the thread-safe wrapper entirely.
public static bool CpuCycleUsesGpu { get; set; }
private static KernelContainer GetKernels(Accelerator accelerator)
{
return KernelCache.GetOrAdd(accelerator, _ => new KernelContainer());
}
// Ensures the small cycles table is uploaded to the device for the given accelerator.
// Returns the ArrayView to pass into kernels (when kernels are extended to accept it).
public static ArrayView1D<ulong, Stride1D.Dense> EnsureSmallCyclesOnDevice(Accelerator accelerator)
{
var kernels = GetKernels(accelerator);
if (kernels.SmallCycles is { } buffer)
{
return buffer.View;
}
// Ensure single upload per accelerator even if multiple threads race here.
lock (kernels) // TODO: Remove this lock by pre-uploading the immutable small-cycle snapshot during initialization; once no mutation happens at runtime, the pool must expose a simple reference without synchronization.
{
if (kernels.SmallCycles is { } existing)
{
return existing.View;
}
var host = MersenneDivisorCycles.Shared.ExportSmallCyclesSnapshot(); // TODO: Preload this device buffer during startup and keep it immutable so we can delete the lock above in favor of the preloaded snapshot.
var device = accelerator.Allocate1D<ulong>(host.Length);
device.View.CopyFromCPU(host);
kernels.SmallCycles = device;
return device.View;
}
}
public static ResiduePrimeViews EnsureSmallPrimesOnDevice(Accelerator accelerator)
{
var kernels = GetKernels(accelerator);
if (kernels.SmallPrimesLastOne is { } lastOne &&
kernels.SmallPrimesLastSeven is { } lastSeven &&
kernels.SmallPrimesPow2LastOne is { } lastOnePow2 &&
kernels.SmallPrimesPow2LastSeven is { } lastSevenPow2)
{
return new ResiduePrimeViews(lastOne.View, lastSeven.View, lastOnePow2.View, lastSevenPow2.View);
}
lock (kernels) // TODO: Inline these small-prime uploads into startup initialization alongside the small-cycle snapshot so we can drop runtime locking and keep the GPU pool free of synchronization.
{
if (kernels.SmallPrimesLastOne is { } existingLastOne &&
kernels.SmallPrimesLastSeven is { } existingLastSeven &&
kernels.SmallPrimesPow2LastOne is { } existingLastOnePow2 &&
kernels.SmallPrimesPow2LastSeven is { } existingLastSevenPow2)
{
return new ResiduePrimeViews(existingLastOne.View, existingLastSeven.View, existingLastOnePow2.View, existingLastSevenPow2.View);
}
var hostLastOne = PrimesGenerator.SmallPrimesLastOne;
var hostLastSeven = PrimesGenerator.SmallPrimesLastSeven;
var hostLastOnePow2 = PrimesGenerator.SmallPrimesPow2LastOne;
var hostLastSevenPow2 = PrimesGenerator.SmallPrimesPow2LastSeven;
var deviceLastOne = accelerator.Allocate1D<uint>(hostLastOne.Length);
deviceLastOne.View.CopyFromCPU(hostLastOne);
var deviceLastSeven = accelerator.Allocate1D<uint>(hostLastSeven.Length);
deviceLastSeven.View.CopyFromCPU(hostLastSeven);
var deviceLastOnePow2 = accelerator.Allocate1D<ulong>(hostLastOnePow2.Length);
deviceLastOnePow2.View.CopyFromCPU(hostLastOnePow2);
var deviceLastSevenPow2 = accelerator.Allocate1D<ulong>(hostLastSevenPow2.Length);
deviceLastSevenPow2.View.CopyFromCPU(hostLastSevenPow2);
kernels.SmallPrimesLastOne = deviceLastOne;
kernels.SmallPrimesLastSeven = deviceLastSeven;
kernels.SmallPrimesPow2LastOne = deviceLastOnePow2;
kernels.SmallPrimesPow2LastSeven = deviceLastSevenPow2;
return new ResiduePrimeViews(deviceLastOne.View, deviceLastSeven.View, deviceLastOnePow2.View, deviceLastSevenPow2.View);
}
}
public static GpuKernelLease GetKernel(bool useGpuOrder)
{
var limiter = GpuPrimeWorkLimiter.Acquire();
var gpu = RentPreferred(preferCpu: !useGpuOrder);
var accelerator = gpu.Accelerator;
var kernels = GetKernels(accelerator);
return new(limiter, gpu, kernels);
}
/// <summary>
/// Runs a GPU action with an acquired accelerator and stream.
/// </summary>
/// <param name="action">Action to run with (Accelerator, Stream).</param>
public static void Run(Action<Accelerator, AcceleratorStream> action)
{
var lease = GetKernel(useGpuOrder: true);
var execution = lease.EnterExecutionScope();
var accelerator = lease.Accelerator;
var stream = accelerator.CreateStream();
action(accelerator, stream);
stream.Dispose();
execution.Dispose();
lease.Dispose();
}
}