爲何編寫TaskSchedulerEx類?html
由於.NET默認線程池只有一個線程池,若是某個批量任務一直佔着大量線程,甚至耗盡默認線程池,則會嚴重影響應用程序域中其它任務或批量任務的性能。數據庫
特色:編程
一、使用獨立線程池,線程池中線程分爲核心線程和輔助線程,輔助線程會動態增長和釋放,且總線程數不大於參數_maxThreadCount瀏覽器
二、無縫兼容Task,使用上和Task同樣,能夠用它來實現異步,參見:C# async await 異步執行方法封裝 替代 BackgroundWorker網絡
三、隊列中還沒有執行的任務能夠取消異步
四、經過擴展類TaskHelper實現任務分組async
五、和SmartThreadPool對比,優勢是無縫兼容Task類,和Task類使用沒有區別,由於它自己就是對Task、TaskScheduler的擴展,因此Task類的ContinueWith、WaitAll等方法它都支持,以及兼容async、await異步編程ide
六、代碼量至關精簡,TaskSchedulerEx類只有260多行代碼異步編程
七、池中的線程數量會根據負載自動增減,支持,但沒有SmartThreadPool智能,爲了性能,使用了比較笨的方式實現,不知道你們有沒有既智能,性能又高的方案,我有一個思路,在定時器中計算每一個任務執行平均耗時,而後使用公式(線程數 = CPU核心數 * ( 本地計算時間 + 等待時間 ) / 本地計算時間)來計算最佳線程數,而後按最佳線程數來動態建立線程,但這個計算過程可能會犧牲性能函數
對比SmartThreadPool:
TaskSchedulerEx類代碼(使用BlockingCollection,當線程數大於200時,CPU佔用高,線程數小於100時,CPU佔用正常):
using System; using System.Collections.Concurrent; using System.Collections.Generic; using System.Linq; using System.Runtime.InteropServices; using System.Text; using System.Threading; using System.Threading.Tasks; namespace Utils { public class TaskSchedulerEx : TaskScheduler, IDisposable { #region 外部方法 [DllImport("kernel32.dll", EntryPoint = "SetProcessWorkingSetSize")] public static extern int SetProcessWorkingSetSize(IntPtr process, int minSize, int maxSize); #endregion #region 變量屬性事件 private BlockingCollection<Task> _tasks = new BlockingCollection<Task>(); List<Thread> _threadList = new List<Thread>(); private int _threadCount = 0; private int _maxThreadCount = 0; private int _timeOut = Timeout.Infinite; private int _extTimeOut = 3000; private Task _tempTask; private int _activeThreadCount = 0; private System.Timers.Timer _timer; private object _lockCreateTimer = new object(); /// <summary> /// 活躍線程數 /// </summary> public int ActiveThreadCount { get { return _activeThreadCount; } } /// <summary> /// 核心線程數 /// </summary> public int CoreThreadCount { get { return _threadCount; } } /// <summary> /// 最大線程數 /// </summary> public int MaxThreadCount { get { return _maxThreadCount; } } #endregion #region 構造函數 public TaskSchedulerEx(int threadCount = 10, int maxThreadCount = 20) { _maxThreadCount = maxThreadCount; CreateThreads(threadCount); } #endregion #region override GetScheduledTasks protected override IEnumerable<Task> GetScheduledTasks() { return _tasks; } #endregion #region override TryExecuteTaskInline protected override bool TryExecuteTaskInline(Task task, bool taskWasPreviouslyQueued) { return false; } #endregion #region override QueueTask protected override void QueueTask(Task task) { _tasks.Add(task); } #endregion #region 資源釋放 /// <summary> /// 資源釋放 /// 若是尚有任務在執行,則會在調用此方法的線程上引起System.Threading.ThreadAbortException,請使用Task.WaitAll等待任務執行完畢後,再調用該方法 /// </summary> public void Dispose() { if (_timer != null) { _timer.Stop(); _timer.Dispose(); _timer = null; } _timeOut = 100; foreach (Thread item in _threadList) { item.Abort(); Interlocked.Decrement(ref _activeThreadCount); } _threadList.Clear(); GC.Collect(); GC.WaitForPendingFinalizers(); if (Environment.OSVersion.Platform == PlatformID.Win32NT) { SetProcessWorkingSetSize(System.Diagnostics.Process.GetCurrentProcess().Handle, -1, -1); } } #endregion #region 建立線程池 /// <summary> /// 建立線程池 /// </summary> private void CreateThreads(int? threadCount = null) { if (threadCount != null) _threadCount = threadCount.Value; _timeOut = Timeout.Infinite; for (int i = 0; i < _threadCount; i++) { Interlocked.Increment(ref _activeThreadCount); Thread thread = new Thread(new ThreadStart(() => { Task task; while (_tasks.TryTake(out task, _timeOut)) { CreateTimer(); TryExecuteTask(task); } })); thread.IsBackground = true; thread.Start(); _threadList.Add(thread); } } #endregion #region 建立線程 /// <summary> /// 建立線程 /// </summary> private void CreateThread() { Interlocked.Increment(ref _activeThreadCount); Thread thread = null; thread = new Thread(new ThreadStart(() => { Task task; while (_tasks.TryTake(out task, _extTimeOut)) { TryExecuteTask(task); } Interlocked.Decrement(ref _activeThreadCount); if (_activeThreadCount == _threadCount) { GC.Collect(); GC.WaitForPendingFinalizers(); if (Environment.OSVersion.Platform == PlatformID.Win32NT) { SetProcessWorkingSetSize(System.Diagnostics.Process.GetCurrentProcess().Handle, -1, -1); } } if (thread != null) { thread.Abort(); thread = null; } })); thread.IsBackground = true; thread.Start(); } #endregion #region 建立定時器 private void CreateTimer() { if (_timer == null) //_timer不爲空時,跳過,不走lock,提高性能 { lock (_lockCreateTimer) { if (_timer == null) { int interval = 20; _timer = new System.Timers.Timer(); _timer.Interval = 1000; _timer.Elapsed += (s, e) => { if (_timer.Interval != interval) _timer.Interval = interval; if (_activeThreadCount >= _threadCount && _activeThreadCount < _maxThreadCount) { if (_tasks.Count > 0) { CreateThread(); } else { if (_timer != null) { _timer.Stop(); _timer.Dispose(); _timer = null; } } } }; _timer.Start(); } } } } #endregion #region 所有取消 /// <summary> /// 所有取消 /// 當前正在執行的任務沒法取消,取消的只是後續任務,至關於AbortAll /// </summary> public void CancelAll() { while (_tasks.TryTake(out _tempTask)) { } } #endregion } }
TaskSchedulerEx類代碼(使用ConcurrentQueue,測試500個線程,CPU佔用0%-2%,正常):
using System; using System.Collections.Concurrent; using System.Collections.Generic; using System.Linq; using System.Runtime.InteropServices; using System.Text; using System.Threading; using System.Threading.Tasks; namespace Utils { /// <summary> /// TaskScheduler擴展 /// 每一個實例都是獨立線程池 /// </summary> public class TaskSchedulerEx : TaskScheduler, IDisposable { #region 外部方法 [DllImport("kernel32.dll", EntryPoint = "SetProcessWorkingSetSize")] public static extern int SetProcessWorkingSetSize(IntPtr process, int minSize, int maxSize); #endregion #region 變量屬性事件 private ConcurrentQueue<Task> _tasks = new ConcurrentQueue<Task>(); List<Thread> _coreThreadList = new List<Thread>(); private int _coreThreadCount = 0; private int _maxThreadCount = 0; private int _auxiliaryThreadTimeOut = 20000; //輔助線程釋放時間 private int _activeThreadCount = 0; private System.Timers.Timer _timer; private object _lockCreateTimer = new object(); private bool _run = true; /// <summary> /// 活躍線程數 /// </summary> public int ActiveThreadCount { get { return _activeThreadCount; } } /// <summary> /// 核心線程數 /// </summary> public int CoreThreadCount { get { return _coreThreadCount; } } /// <summary> /// 最大線程數 /// </summary> public int MaxThreadCount { get { return _maxThreadCount; } } #endregion #region 構造函數 /// <summary> /// TaskScheduler擴展 /// 每一個實例都是獨立線程池 /// </summary> /// <param name="coreThreadCount">核心線程數(大於或等於0,不宜過大)(若是是一次性使用,則設置爲0比較合適)</param> /// <param name="maxThreadCount">最大線程數</param> public TaskSchedulerEx(int coreThreadCount = 10, int maxThreadCount = 20) { _maxThreadCount = maxThreadCount; CreateCoreThreads(coreThreadCount); } #endregion #region override GetScheduledTasks protected override IEnumerable<Task> GetScheduledTasks() { return _tasks; } #endregion #region override TryExecuteTaskInline protected override bool TryExecuteTaskInline(Task task, bool taskWasPreviouslyQueued) { return false; } #endregion #region override QueueTask protected override void QueueTask(Task task) { CreateTimer(); _tasks.Enqueue(task); } #endregion #region 資源釋放 /// <summary> /// 資源釋放 /// 若是尚有任務在執行,則會在調用此方法的線程上引起System.Threading.ThreadAbortException,請使用Task.WaitAll等待任務執行完畢後,再調用該方法 /// </summary> public void Dispose() { _run = false; if (_timer != null) { _timer.Stop(); _timer.Dispose(); _timer = null; } foreach (Thread item in _coreThreadList) { item.Abort(); Interlocked.Decrement(ref _activeThreadCount); } _coreThreadList.Clear(); GC.Collect(); GC.WaitForPendingFinalizers(); if (Environment.OSVersion.Platform == PlatformID.Win32NT) { SetProcessWorkingSetSize(System.Diagnostics.Process.GetCurrentProcess().Handle, -1, -1); } } #endregion #region 建立核心線程池 /// <summary> /// 建立核心線程池 /// </summary> private void CreateCoreThreads(int? coreThreadCount = null) { if (coreThreadCount != null) _coreThreadCount = coreThreadCount.Value; for (int i = 0; i < _coreThreadCount; i++) { Interlocked.Increment(ref _activeThreadCount); Thread thread = new Thread(new ThreadStart(() => { Task task; while (_run) { if (_tasks.TryDequeue(out task)) { TryExecuteTask(task); } else { Thread.Sleep(10); } } })); thread.IsBackground = true; thread.Start(); _coreThreadList.Add(thread); } } #endregion #region 建立輔助線程 /// <summary> /// 建立輔助線程 /// </summary> private void CreateThread() { Interlocked.Increment(ref _activeThreadCount); Thread thread = null; thread = new Thread(new ThreadStart(() => { Task task; DateTime dt = DateTime.Now; while (_run && DateTime.Now.Subtract(dt).TotalMilliseconds < _auxiliaryThreadTimeOut) { if (_tasks.TryDequeue(out task)) { TryExecuteTask(task); dt = DateTime.Now; } else { Thread.Sleep(100); } } Interlocked.Decrement(ref _activeThreadCount); if (_activeThreadCount == _coreThreadCount) { GC.Collect(); GC.WaitForPendingFinalizers(); if (Environment.OSVersion.Platform == PlatformID.Win32NT) { SetProcessWorkingSetSize(System.Diagnostics.Process.GetCurrentProcess().Handle, -1, -1); } } if (thread != null) { thread.Abort(); thread = null; } })); thread.IsBackground = true; thread.Start(); } #endregion #region 建立定時器 private void CreateTimer() { if (_timer == null) //_timer不爲空時,跳過,不走lock,提高性能 { lock (_lockCreateTimer) { if (_timer == null) { int interval = 20; _timer = new System.Timers.Timer(); _timer.Interval = _coreThreadCount == 0 ? 1 : 500; _timer.Elapsed += (s, e) => { if (_timer.Interval != interval) _timer.Interval = interval; if (_activeThreadCount >= _coreThreadCount && _activeThreadCount < _maxThreadCount) { if (_tasks.Count > 0) { CreateThread(); } else { if (_timer != null) { _timer.Stop(); _timer.Dispose(); _timer = null; } } } }; _timer.Start(); } } } } #endregion #region 所有取消 /// <summary> /// 所有取消 /// 當前正在執行的任務沒法取消,取消的只是後續任務,至關於AbortAll /// </summary> public void CancelAll() { Task tempTask; while (_tasks.TryDequeue(out tempTask)) { } } #endregion } }
RunHelper類代碼:
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; using System.Threading.Tasks; namespace Utils { /// <summary> /// 線程工具類 /// </summary> public static class RunHelper { #region 變量屬性事件 #endregion #region 線程中執行 /// <summary> /// 線程中執行 /// </summary> public static Task Run(this TaskScheduler scheduler, Action<object> doWork, object arg = null, Action<Exception> errorAction = null) { return Task.Factory.StartNew((obj) => { try { doWork(obj); } catch (Exception ex) { if (errorAction != null) errorAction(ex); LogUtil.Error(ex, "ThreadUtil.Run錯誤"); } }, arg, CancellationToken.None, TaskCreationOptions.None, scheduler); } #endregion #region 線程中執行 /// <summary> /// 線程中執行 /// </summary> public static Task Run(this TaskScheduler scheduler, Action doWork, Action<Exception> errorAction = null) { return Task.Factory.StartNew(() => { try { doWork(); } catch (Exception ex) { if (errorAction != null) errorAction(ex); LogUtil.Error(ex, "ThreadUtil.Run錯誤"); } }, CancellationToken.None, TaskCreationOptions.None, scheduler); } #endregion #region 線程中執行 /// <summary> /// 線程中執行 /// </summary> public static Task<T> Run<T>(this TaskScheduler scheduler, Func<object, T> doWork, object arg = null, Action<Exception> errorAction = null) { return Task.Factory.StartNew<T>((obj) => { try { return doWork(obj); } catch (Exception ex) { if (errorAction != null) errorAction(ex); LogUtil.Error(ex, "ThreadUtil.Run錯誤"); return default(T); } }, arg, CancellationToken.None, TaskCreationOptions.None, scheduler); } #endregion #region 線程中執行 /// <summary> /// 線程中執行 /// </summary> public static Task<T> Run<T>(this TaskScheduler scheduler, Func<T> doWork, Action<Exception> errorAction = null) { return Task.Factory.StartNew<T>(() => { try { return doWork(); } catch (Exception ex) { if (errorAction != null) errorAction(ex); LogUtil.Error(ex, "ThreadUtil.Run錯誤"); return default(T); } }, CancellationToken.None, TaskCreationOptions.None, scheduler); } #endregion #region 線程中執行 /// <summary> /// 線程中執行 /// </summary> public static async Task<T> RunAsync<T>(this TaskScheduler scheduler, Func<object, T> doWork, object arg = null, Action<Exception> errorAction = null) { return await Task.Factory.StartNew<T>((obj) => { try { return doWork(obj); } catch (Exception ex) { if (errorAction != null) errorAction(ex); LogUtil.Error(ex, "ThreadUtil.Run錯誤"); return default(T); } }, arg, CancellationToken.None, TaskCreationOptions.None, scheduler); } #endregion #region 線程中執行 /// <summary> /// 線程中執行 /// </summary> public static async Task<T> RunAsync<T>(this TaskScheduler scheduler, Func<T> doWork, Action<Exception> errorAction = null) { return await Task.Factory.StartNew<T>(() => { try { return doWork(); } catch (Exception ex) { if (errorAction != null) errorAction(ex); LogUtil.Error(ex, "ThreadUtil.Run錯誤"); return default(T); } }, CancellationToken.None, TaskCreationOptions.None, scheduler); } #endregion } }
TaskHelper擴展類(代碼中LimitedTaskScheduler改成TaskSchedulerEx便可)(這個任務分類有點多,每一個任務分類的核心線程通常是不釋放的,一直佔着線程,算不算濫用):
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Utils { /// <summary> /// Task幫助類基類 /// </summary> public class TaskHelper { #region UI任務 private static LimitedTaskScheduler _UITask; /// <summary> /// UI任務(4個線程) /// </summary> public static LimitedTaskScheduler UITask { get { if (_UITask == null) _UITask = new LimitedTaskScheduler(4); return _UITask; } } #endregion #region 菜單任務 private static LimitedTaskScheduler _MenuTask; /// <summary> /// 菜單任務 /// </summary> public static LimitedTaskScheduler MenuTask { get { if (_MenuTask == null) _MenuTask = new LimitedTaskScheduler(2); return _MenuTask; } } #endregion #region 計算任務 private static LimitedTaskScheduler _CalcTask; /// <summary> /// 計算任務(8個線程) /// </summary> public static LimitedTaskScheduler CalcTask { get { if (_CalcTask == null) _CalcTask = new LimitedTaskScheduler(8); return _CalcTask; } } #endregion #region 網絡請求 private static LimitedTaskScheduler _RequestTask; /// <summary> /// 網絡請求(32個線程) /// </summary> public static LimitedTaskScheduler RequestTask { get { if (_RequestTask == null) _RequestTask = new LimitedTaskScheduler(32); return _RequestTask; } } #endregion #region 數據庫任務 private static LimitedTaskScheduler _DBTask; /// <summary> /// 數據庫任務(32個線程) /// </summary> public static LimitedTaskScheduler DBTask { get { if (_DBTask == null) _DBTask = new LimitedTaskScheduler(32); return _DBTask; } } #endregion #region IO任務 private static LimitedTaskScheduler _IOTask; /// <summary> /// IO任務(8個線程) /// </summary> public static LimitedTaskScheduler IOTask { get { if (_IOTask == null) _IOTask = new LimitedTaskScheduler(8); return _IOTask; } } #endregion #region 首頁任務 private static LimitedTaskScheduler _MainPageTask; /// <summary> /// 首頁任務(16個線程) /// </summary> public static LimitedTaskScheduler MainPageTask { get { if (_MainPageTask == null) _MainPageTask = new LimitedTaskScheduler(16); return _MainPageTask; } } #endregion #region 圖片加載任務 private static LimitedTaskScheduler _LoadImageTask; /// <summary> /// 圖片加載任務(32個線程) /// </summary> public static LimitedTaskScheduler LoadImageTask { get { if (_LoadImageTask == null) _LoadImageTask = new LimitedTaskScheduler(32); return _LoadImageTask; } } #endregion #region 瀏覽器任務 private static LimitedTaskScheduler _BrowserTask; /// <summary> /// 瀏覽器任務 /// </summary> public static LimitedTaskScheduler BrowserTask { get { if (_BrowserTask == null) _BrowserTask = new LimitedTaskScheduler(2); return _BrowserTask; } } #endregion } }
Form1.cs測試代碼:
using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Management; using System.Reflection; using System.Runtime.InteropServices; using System.Text; using System.Threading; using System.Threading.Tasks; using System.Windows.Forms; using Utils; namespace test { public partial class Form1 : Form { private TaskSchedulerEx _taskSchedulerEx = null; private TaskSchedulerEx _taskSchedulerExSmall = null; private TaskSchedulerEx _task = null; public Form1() { InitializeComponent(); _taskSchedulerEx = new TaskSchedulerEx(50, 500); _taskSchedulerExSmall = new TaskSchedulerEx(5, 50); _task = new TaskSchedulerEx(2, 10); } private void Form1_Load(object sender, EventArgs e) { } /// <summary> /// 模擬大量網絡請求任務 /// </summary> private void button1_Click(object sender, EventArgs e) { DoTask(_taskSchedulerEx, 200000, 1000, 20); } /// <summary> /// 模擬CPU密集型任務 /// </summary> private void button2_Click(object sender, EventArgs e) { DoTask(_taskSchedulerEx, 100000, 2000, 1); } /// <summary> /// 模擬大量網絡請求任務 /// </summary> private void button3_Click(object sender, EventArgs e) { DoTask(_taskSchedulerExSmall, 2000, 100, 20); } /// <summary> /// 模擬CPU密集型任務 /// </summary> private void button4_Click(object sender, EventArgs e) { DoTask(_taskSchedulerExSmall, 2000, 100, 1); } /// <summary> /// 模擬任務 /// </summary> /// <param name="scheduler">scheduler</param> /// <param name="taskCount">任務數量</param> /// <param name="logCount">每隔多少條數據打一個日誌</param> /// <param name="delay">模擬延遲或耗時(毫秒)</param> private void DoTask(TaskSchedulerEx scheduler, int taskCount, int logCount, int delay) { _task.Run(() => { Log("開始"); DateTime dt = DateTime.Now; List<Task> taskList = new List<Task>(); for (int i = 1; i <= taskCount; i++) { Task task = scheduler.Run((obj) => { var k = (int)obj; Thread.Sleep(delay); //模擬延遲或耗時 if (k % logCount == 0) { Log("最大線程數:" + scheduler.MaxThreadCount + " 核心線程數:" + scheduler.CoreThreadCount + " 活躍線程數:" + scheduler.ActiveThreadCount.ToString().PadLeft(4, ' ') + " 處理數/總數:" + k + " / " + taskCount); } }, i, (ex) => { Log(ex.Message); }); taskList.Add(task); } Task.WaitAll(taskList.ToArray()); double d = DateTime.Now.Subtract(dt).TotalSeconds; Log("完成,耗時:" + d + "秒"); }); } private void Form1_FormClosed(object sender, FormClosedEventArgs e) { if (_taskSchedulerEx != null) { _taskSchedulerEx.Dispose(); //釋放資源 _taskSchedulerEx = null; } } } }
測試截圖: