المفاضلة بين الإنتاجية وزمن الاستجابة

معدل النقل مقابل زمن الاستجابة

نمط المعالجة لكل عنصر

using System;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;

public class Program
{
  // Simulate small per-item cost
  static void HandleItem(int x)
  {
    // Fixed overhead per item
    Thread.SpinWait(20000); // tiny CPU work
  }

  public static void Main(string[] args)
  {
    int n = 200;
    Stopwatch sw = Stopwatch.StartNew();
    for (int i = 0; i < n; i++)
    {
      HandleItem(i);         // process immediately (no batching)
      // emit result right away (low latency style)
    }
    sw.Stop();
    Console.WriteLine("Per-item style: {0} ms for {1} items", sw.ElapsedMilliseconds, n);
  }
}

نمط التجميع

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading;

public class Program
{
  static void ProcessBatch(List<int> batch)
  {
    // Amortize overhead across the whole batch
    Thread.SpinWait(20000);        // one-time overhead
    for (int i = 0; i < batch.Count; i++)
    {
      // small per-record work
      int val = batch[i] * 2;
      if (val == int.MinValue) { } // keep compiler from dropping work
    }
  }

  public static void Main(string[] args)
  {
    int n = 200;
    int batchSize = 20;
    List<int> current = new List<int>(batchSize);

    Stopwatch sw = Stopwatch.StartNew();
    for (int i = 0; i < n; i++)
    {
      current.Add(i);
      if (current.Count == batchSize)
      {
        ProcessBatch(current);
        current.Clear(); // emit results after the batch finishes
      }
    }
    if (current.Count > 0) ProcessBatch(current);
    sw.Stop();

    Console.WriteLine("Batch style: {0} ms for {1} items (batch={2})", sw.ElapsedMilliseconds, n, batchSize);
  }
}

ضبط التوازي

using System;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;

public class Program
{
  static void Work(int x)
  {
    // CPU-bound unit
    Thread.SpinWait(40000);
  }

  public static void Main(string[] args)
  {
    int[] data = new int[200];
    for (int i = 0; i < data.Length; i++) data[i] = i;

    foreach (int dop in new int[] { 1, 2, 4 })
    {
      var opt = new ParallelOptions();
      opt.MaxDegreeOfParallelism = dop;

      Stopwatch sw = Stopwatch.StartNew();
      Parallel.ForEach(data, opt, Work);
      sw.Stop();

      Console.WriteLine("DOP={0} -> {1} ms", dop, sw.ElapsedMilliseconds);
    }
  }
}

فكرة الدفعات الصغيرة

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;

public class Program
{
  static void ProcessBatch(List<int> batch)
  {
    Thread.SpinWait(15000); // small shared overhead
    for (int i = 0; i < batch.Count; i++) Thread.SpinWait(2000);
  }

  public static void Main(string[] args)
  {
    int n = 200;
    int micro = 5; // micro-batch size
    List<int> buf = new List<int>(micro);
    Stopwatch sw = Stopwatch.StartNew();

    for (int i = 0; i < n; i++)
    {
      buf.Add(i);
      if (buf.Count == micro)
      {
        ProcessBatch(buf);
        buf.Clear(); // emit more frequently than big batches
      }
    }
    if (buf.Count > 0) ProcessBatch(buf);

    sw.Stop();
    Console.WriteLine("Micro-batch (size={0}): {1} ms", micro, sw.ElapsedMilliseconds);
  }
}

نصائح الضبط

المفاضلة بين معدل النقل وزمن الاستجابة

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