110 lines
2.8 KiB
C#
110 lines
2.8 KiB
C#
using System.Diagnostics;
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namespace Nerfed.Runtime;
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public sealed class JobSystem : IDisposable
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{
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public static readonly JobSystem Default = new JobSystem();
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private Thread[] workers;
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private SemaphoreSlim startSignal;
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private CountdownEvent completionEvent;
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private volatile bool running;
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// Shared per-dispatch state written by main thread before workers wake.
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private volatile Action<int> currentAction;
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private int workCount;
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private int nextIndex; // grabbed with Interlocked.Increment for work-stealing
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public int WorkerCount => workers?.Length ?? 0;
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public bool IsInitialized => workers != null;
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public void Initialize(int threadCount = -1)
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{
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if (IsInitialized)
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{
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throw new InvalidOperationException("JobSystem is already initialized. Call Shutdown first.");
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}
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threadCount = threadCount < 0
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? Math.Max(1, Environment.ProcessorCount - 2)
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: Math.Max(1, threadCount);
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running = true;
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startSignal = new SemaphoreSlim(0);
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completionEvent = new CountdownEvent(1);
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workers = new Thread[threadCount];
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for (int i = 0; i < threadCount; i++)
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{
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workers[i] = new Thread(WorkerLoop)
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{
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IsBackground = true,
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Name = $"Job-{i}",
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};
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workers[i].Start();
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}
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}
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public void Dispatch(int count, Action<int> action)
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{
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if (count <= 0) return;
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if (!IsInitialized)
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{
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// Safe fallback: run inline if Initialize was never called.
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for (int i = 0; i < count; i++)
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action(i);
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return;
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}
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currentAction = action;
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workCount = count;
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Volatile.Write(ref nextIndex, 0);
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completionEvent.Reset(workers.Length);
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startSignal.Release(workers.Length);
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completionEvent.Wait();
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currentAction = null;
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}
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public void Shutdown()
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{
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if (!IsInitialized) return;
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running = false;
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startSignal.Release(workers.Length); // wake all workers so they can see running=false and exit
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foreach (Thread t in workers)
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t.Join();
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completionEvent.Dispose();
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startSignal.Dispose();
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workers = null;
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}
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public void Dispose() => Shutdown();
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private void WorkerLoop()
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{
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while (true)
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{
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startSignal.Wait();
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if (!running) return;
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Action<int> action = currentAction;
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int total = workCount;
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while (true)
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{
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int index = Interlocked.Increment(ref nextIndex) - 1;
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if (index >= total) break;
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action(index);
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}
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completionEvent.Signal();
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}
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}
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}
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