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线程与并行性能

task-parallel-library multithreading c#

FIre Panda · 技术社区 · 6 年前

我正在努力理解螺纹和 平行的 . 我创建了两个函数,一个用于并行,另一个用于调用的线程。调用 10线程 似乎是更快 ,有人能解释一下吗?会螺纹使用 多处理器 在系统中可用(并行执行)还是只执行 时间分割 关于clr?

public static bool ParallelProcess()
{
    Stopwatch sw = new Stopwatch();

    sw.Start();
    Parallel.For(0, 10, x =>
    {
        Console.WriteLine(string.Format("Printing {0} thread = {1}", x,
            Thread.CurrentThread.ManagedThreadId));
        Thread.Sleep(3000);
    });
    sw.Stop();
    Console.WriteLine(string.Format("Time in secs {0}", sw.Elapsed.Seconds));

    return true;
}

public static bool ParallelThread()
{
    Stopwatch sw = new Stopwatch();

    sw.Start();
    for (int i = 0; i < 10; i++)
    {
        Thread t = new Thread(new ThreadStart(Thread1));
        t.Start();
        if (i == 9)
            t.Join();
    }
    sw.Stop();
    Console.WriteLine(string.Format("Time in secs {0}", sw.Elapsed.Seconds));

    return true;
}

private static void Thread1()
{
    Console.WriteLine(string.Format("Printing {0} thread = {1}", 0,
           Thread.CurrentThread.ManagedThreadId));
    Thread.Sleep(3000);
}

当在下面的方法中调用时,parallel.for花费了两次时间,然后是线程。

Algo.ParallelThread(); //took 3 secs
Algo.ParallelProcess();  //took 6 secs

4 回复 | 直到 6 年前

Enigmativity 6 年前

sw.Elapsed.Seconds int 1 sw.Elapsed.TotalSeconds double

Parallel.For new Thread(() => ...)

Thread.Sleep(3000);

new Thread

public static bool ParallelProcess()
{
    Stopwatch sw = new Stopwatch();

    sw.Start();
    Parallel.For(0, 10, x =>
    {
        Console.WriteLine(string.Format("Printing {0} thread = {1}", x, Thread.CurrentThread.ManagedThreadId));
    });
    sw.Stop();
    Console.WriteLine(string.Format("Time in secs {0}", sw.Elapsed.TotalMilliseconds));

    return true;
}

public static bool ParallelThread()
{
    Stopwatch sw = new Stopwatch();

    sw.Start();
    var threads = Enumerable.Range(0, 10).Select(x => new Thread(new ThreadStart(Thread1))).ToList();
    foreach (var thread in threads) thread.Start();
    foreach (var thread in threads) thread.Join();
    sw.Stop();

    Console.WriteLine(string.Format("Time in secs {0}", sw.Elapsed.TotalMilliseconds));

    return true;
}

private static void Thread1()
{
    Console.WriteLine(string.Format("Printing {0} thread = {1}", 0, Thread.CurrentThread.ManagedThreadId));  
}

ParallelProcess();
ParallelThread();
ParallelProcess();
ParallelThread();
ParallelProcess();
ParallelThread();

Time in secs 3.8617
Time in secs 4.7719
Time in secs 0.3633
Time in secs 1.6332
Time in secs 0.3551
Time in secs 1.6148

Saeb Amini 6 年前

Parallel

ThreadPool.SetMinThreads(100, 100)

Theraot 6 年前

ParallelThread ParallelProcess

public static bool ParallelThread()
{
    Stopwatch sw = new Stopwatch();

    sw.Start();
    var threads = new Thread[10];
    for (int i = 0; i < 10; i++)
    {
        int x = i;
        threads[i] = new Thread(() => Thread1(x));
        threads[i].Start();
    }
    for (int i = 0; i < 10; i++)
    {
        threads[i].Join();
    }
    sw.Stop();
    Console.WriteLine(string.Format("Time in secs {0}", sw.Elapsed.Seconds));

    return true;
}

private static void Thread1(int x)
{
    Console.WriteLine(string.Format("Printing {0} thread = {1}", x,
           Thread.CurrentThread.ManagedThreadId));
    Thread.Sleep(3000);
}

ThreadPool

public static bool ParallelThread()
{
    Stopwatch sw = new Stopwatch();

    sw.Start();
    var events = new ManualResetEvent[10];
        for (int i = 0; i < 10; i++)
    {
        int x = i;
        events[x] = new ManualResetEvent(false);
        ThreadPool.QueueUserWorkItem
            (
                _ =>
                {
                    Thread1(x);
                    events[x].Set();
                }
            );
    }
    for (int i = 0; i < 10; i++)
    {
        events[i].WaitOne();
    }
    sw.Stop();
    Console.WriteLine(string.Format("Time in secs {0}", sw.Elapsed.Seconds));

    return true;
}

private static void Thread1(int x)
{
    Console.WriteLine(string.Format("Printing {0} thread = {1}", x,
           Thread.CurrentThread.ManagedThreadId));
    Thread.Sleep(3000);
}

WaitAll STAThread

Thread.Sleep(3000)

Console.WriteLine

void Main()
{
    ParallelThread();
    ParallelProcess();
}

public static bool ParallelProcess()
{
    Stopwatch sw = new Stopwatch();

    sw.Start();
    Parallel.For(0, 100, x =>
    {
        /*Console.WriteLine(string.Format("Printing {0} thread = {1}", x,
            Thread.CurrentThread.ManagedThreadId));*/
        Thread.Sleep(3000);
    });
    sw.Stop();
    Console.WriteLine(string.Format("Time in secs {0}", sw.Elapsed.Seconds));

    return true;
}

public static bool ParallelThread()
{
    Stopwatch sw = new Stopwatch();

    sw.Start();
    var events = new ManualResetEvent[100];
        for (int i = 0; i < 100; i++)
    {
        int x = i;
        events[x] = new ManualResetEvent(false);
        ThreadPool.QueueUserWorkItem
            (
                _ =>
                {
                    Thread1(x);
                    events[x].Set();
                }
            );
    }
    for (int i = 0; i < 100; i++)
    {
        events[i].WaitOne();
    }
    sw.Stop();
    Console.WriteLine(string.Format("Time in secs {0}", sw.Elapsed.Seconds));

    return true;
}

private static void Thread1(int x)
{
    /*Console.WriteLine(string.Format("Printing {0} thread = {1}", x,
           Thread.CurrentThread.ManagedThreadId));*/
    Thread.Sleep(3000);
}

ThreadPool.SetMinThreads(100, 100);

public static bool ParallelThread()
{
    Stopwatch sw = new Stopwatch();

    sw.Start();
    var threads = new Thread[100];
    for (int i = 0; i < 100; i++)
    {
        int x = i;
        threads[i] = new Thread(() => Thread1(x));
        threads[i].Start();
    }
    for (int i = 0; i < 100; i++)
    {
        threads[i].Join();
    }
    sw.Stop();
    Console.WriteLine(string.Format("Time in secs {0}", sw.Elapsed.Seconds));

    return true;
}

private static void Thread1(int x)
{
    /*Console.WriteLine(string.Format("Printing {0} thread = {1}", x,
           Thread.CurrentThread.ManagedThreadId));*/
    Thread.Sleep(3000);
}

Parallel.For ThreadPool.SetMaxThreads(1, 1);

ProcessThread.ProcessorAffinity fibers

-1

user1451111 6 年前

Thread Parallel.For