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stgsharp/StgSharp.Common/Mathematics/Linear/MatrixParallel.cs
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2025-10-09 09:19:00 +08:00

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C#

//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="MatrixParallel.cs"
// Project: StgSharp
// AuthorGroup: Nitload Space
// Copyright (c) Nitload Space. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the “Software”), to deal in the Software without restriction,
// including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software,
// and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:
//
// The above copyright notice and
// this permission notice shall be included in all copies
// or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED “AS IS”,
// WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH
// THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// -----------------------------------------------------------------------
// -----------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Runtime.CompilerServices;
using System.Threading;
namespace StgSharp.Mathematics
{
/*
* Thread wrapping to accelerate matrix operations by dividing threads into groups (wraps).
* For M wraps, each containing an average of N threads, we satisfy the condition M * N = T - 4,
* where T is the total thread count of the CPU. Typically, for modern consumer CPUs, T is around 16.
* For simplicity, let M * N = 16.
*
* The total time complexity for publishing tasks is O(M + N):
* - O(M) accounts for distributing tasks across M wraps.
* - O(N) accounts for threads within each wrap fetching tasks from the wrap queue.
*
* Using the inequality Sqrt(M * N) <= (M + N) / 2 (derived from the arithmetic-geometric mean inequality),
* the optimal configuration occurs when M = N. For M * N = 16, this gives M = N = 4.
*
* To ensure compatibility across a wide range of CPU architectures,
* we allow each wrap to contain either 3 or 4 threads, providing flexibility while maintaining efficiency.
*/
public static partial class MatrixParallel
{
// TODO
/*
* 目前认为应当按照如下方式进行调整:
* 1. 使用Queue进行线程束池化
* 2. 一次只能有一个线程进行发布活动(一次只能由一个线程持有)
* 3. 发布任务似乎应当分类进行,分类条件为q = n_task / n_thread
* 3.1 q=0时,不是全部任务束可以参与计算
* 3.2 q>0时,全部任务束可以参与计算
* 4. 后续分为a个q线程,b个q+1线程,然后分到线程束中,同时不保证束内任务同步
* 5. 仅可能保证线程间任务数量差异不超过512
*/
private static Thread[] _threads;
private static readonly (int a, int b)[] LookupTable = [
(1, 1), // 7
(0, 2), // 8 (no non-zero solution)
(3, 0), // 9 (no non-zero solution)
(2, 1), // 10
(1, 2), // 11
(0, 3), // 12 (no non-zero solution)
(3, 1), // 13
(2, 2), // 14
(1, 3), // 15
(4, 1), // 16
(3, 2), // 17
(2, 3), // 18
(1, 4), // 19
(4, 2), // 20
];
private static bool _meaningful;
private static volatile int RemainThreadCount = 0;
private static readonly object _lock = new();
private static ThreadPriority _AfterWork = ThreadPriority.Lowest;
public static bool SupportParallel { get; } = Environment.ProcessorCount > 6;
public static bool IsParallelMeaningful => Environment.ProcessorCount > 6 && IsInitialized;
public static MatrixParallelWrap.Handle LeaderHandle { get; private/**/ set; }
private static bool IsInitialized { get; set; } = false;
private static Queue<IntPtr> LeaderTask { get; set; }
public static void EndParallel()
{
Monitor.Exit(_lock);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static (int count_3, int count_4) FastDecompose(int c)
{
if (c < 7) {
return (0, 0);
}
int t = c - 7;
int k = t / 14;
int d = t % 14;
(int a0, int b0) = LookupTable[d];
return (a0 + (2 * k), b0 + (2 * k));
}
public static void Init()
{
if (IsInitialized) {
return;
}
MatrixParallelFactory.Init();
if (!SupportParallel)
{
IsInitialized = true;
return;
}
int count = Environment.ProcessorCount - 4;
count = count == 5 ? 4 : count;
_threads = new Thread[count];
if (count < 6)
{
if (count == 3)
{
SmallWraps = [ new MatrixParallelWrap(0, count, true) ];
LargeWraps = [];
(LargeWrapCount, SmallWrapCount) = (0, 1);
LeaderHandle = new MatrixParallelWrap.Handle(0, SmallWraps[0]);
} else
{
count = 4;
LargeWraps = [ new MatrixParallelWrap(0, count, true) ];
SmallWraps = [];
(LargeWrapCount, SmallWrapCount) = (1, 0);
LeaderHandle = new MatrixParallelWrap.Handle(0, LargeWraps[0]);
}
} else if (count == 6)
{
SmallWraps = [ new MatrixParallelWrap(0, 3, true), new MatrixParallelWrap(3, 3, false) ];
LargeWraps = [];
(LargeWrapCount, SmallWrapCount) = (0, 2);
LeaderHandle = new MatrixParallelWrap.Handle(0, SmallWraps[0]);
} else
{
(int _3wrap, int _4wrap) = FastDecompose(count);
LargeWraps = new MatrixParallelWrap[_4wrap];
SmallWraps = new MatrixParallelWrap[_3wrap];
int id = 0;
for (int idx = 0; idx < _3wrap; idx++, id += 3) {
SmallWraps[idx] = new MatrixParallelWrap(idx, 3, id == 0);
}
for (int idx = 0; idx < _3wrap + _4wrap; idx++, id += 4) {
LargeWraps[idx] = new MatrixParallelWrap(id, 4, id == 0);
}
LeaderHandle = new MatrixParallelWrap.Handle(0, _3wrap == 0 ? LargeWraps[0] : SmallWraps[0]);
}
LeaderTask = LeaderHandle.Wrap.GetWorkerTaskQueue(0);
IsInitialized = true;
}
public static void LaunchParallel(SleepMode afterWork)
{
RemainThreadCount = _threads.Length;
_AfterWork = (ThreadPriority)afterWork;
SetAllWrap();
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static void LeadParallel()
{
Monitor.Enter(_lock);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static unsafe void MatrixParallelLeaderWork()
{
MatrixParallelWrap.ExecuteTaskPackage(LeaderTask);
_ = Interlocked.Decrement(ref RemainThreadCount);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static void ResetThreadCount()
{
RemainThreadCount = _threads.Length;
}
public static void SetAllWrap()
{
ResetThreadCount();
foreach (MatrixParallelWrap item in LargeWraps) {
item.SchedulerReset.Set();
}
foreach (MatrixParallelWrap item in SmallWraps) {
item.SchedulerReset.Set();
}
}
public unsafe class MatrixParallelWrap
{
private readonly Queue<IntPtr>[] _cache;
private readonly Thread[] _threads;
private readonly ManualResetEventSlim[] _workerReset;
public MatrixParallelWrap(int id, int wrapSize, bool isFirst)
{
ID = id;
int begin = isFirst ? 1 : 0, end = wrapSize - 1;
_cache = new Queue<IntPtr>[wrapSize];
_workerReset = new ManualResetEventSlim[end];
_threads = new Thread[wrapSize];
for (int i = 0; i < end; i++) {
_workerReset[i] = new ManualResetEventSlim(false);
}
for (int i = 0; i < _cache.Length; i++) {
_cache[i] = new Queue<IntPtr>(8);
}
for (int i = begin; i < end; i++)
{
_threads[i] = new Thread(MatrixParallelWorker)
{
IsBackground = true,
Priority = ThreadPriority.BelowNormal,
Name = $"MPT#{ID}_{i}"
};
_threads[i].Start(new Handle(i, this));
}
_threads[end] = new Thread(MatrixParallelScheduler)
{
IsBackground = true,
Priority = ThreadPriority.BelowNormal,
Name = $"MPT#{ID}_{end}*"
};
_threads[end].Start(new Handle(end, this));
}
public int ID { get; init; }
internal ManualResetEventSlim SchedulerReset { get; } = new(false);
public Span<IntPtr> EnqueuePackage(Span<IntPtr> packageSpan)
{
int idx = 0;
for (; idx < _cache.Length; idx++) {
_cache[idx].Enqueue(packageSpan[idx]);
}
return packageSpan[idx..];
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public ManualResetEventSlim GetWorkerResetEvent(int id)
{
return _workerReset[id];
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public Queue<IntPtr> GetWorkerTaskQueue(int idInWrap)
{
return _cache[idInWrap];
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void SetAllWorker()
{
foreach (ManualResetEventSlim item in _workerReset) {
item.Set();
}
}
public record class Handle(int InWrapIndex, MatrixParallelWrap Wrap);
#region ThreadOperation
private static unsafe void MatrixParallelWorker([AllowNull] object obj)
{
Handle handle = (obj as Handle)!;
MatrixParallelWrap wrap = handle.Wrap;
int inWrapIndex = handle.InWrapIndex;
Thread self = Thread.CurrentThread;
ManualResetEventSlim reset = wrap.GetWorkerResetEvent(inWrapIndex);
do
{
reset.Wait();
reset.Reset();
self.Priority = ThreadPriority.Highest;
ExecuteTaskPackage(wrap.GetWorkerTaskQueue(inWrapIndex));
_ = Interlocked.Decrement(ref RemainThreadCount);
self.Priority = _AfterWork;
} while (true);
}
private static unsafe void MatrixParallelScheduler([AllowNull] object obj)
{
Handle handle = (obj as Handle)!;
MatrixParallelWrap wrap = handle.Wrap;
int inWrapIndex = handle.InWrapIndex;
Queue<IntPtr> taskQueue = wrap.GetWorkerTaskQueue(inWrapIndex);
ManualResetEventSlim resetEvent = wrap.SchedulerReset;
Thread self = Thread.CurrentThread;
do
{
resetEvent.Wait();
resetEvent.Reset();
self.Priority = ThreadPriority.Highest;
// TODO task publication to worker in wrap
wrap.SetAllWorker();
ExecuteTaskPackage(taskQueue);
_ = Interlocked.Decrement(ref RemainThreadCount);
self.Priority = _AfterWork;
} while (true);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static unsafe void ExecuteTaskPackage(Queue<IntPtr> taskQueue)
{
while (taskQueue.TryDequeue(out nint handle))
{
MatrixParallelTaskPackageNonGeneric* p = (MatrixParallelTaskPackageNonGeneric*)handle;
switch (p->ComputeMode)
{
case 1:
Compute_Unary(p);
break;
case 2:
Compute_UnaryScalar(p);
break;
case 3:
Compute_Binary(p);
break;
case 4:
Compute_BinaryScalar(p);
break;
default:
break;
}
}
}
#endregion
}
#region wrap field
private static MatrixParallelWrap[] LargeWraps;
private static MatrixParallelWrap[] SmallWraps;
private static int LargeWrapCount;
private static int SmallWrapCount;
#endregion
}
public enum SleepMode
{
QuickWakeup = ThreadPriority.AboveNormal,
NormalSleep = ThreadPriority.BelowNormal,
DeepSleep = ThreadPriority.Lowest,
}
}