| | | 1 | | using AmbientServices.Utilities; |
| | | 2 | | using System.Diagnostics; |
| | | 3 | | using System.Diagnostics.CodeAnalysis; |
| | | 4 | | using System.Reflection; |
| | | 5 | | #if NET5_0_OR_GREATER |
| | | 6 | | using System.Runtime.Versioning; |
| | | 7 | | #endif |
| | | 8 | | namespace AmbientServices |
| | | 9 | | { |
| | | 10 | | /// <summary> |
| | | 11 | | /// A <see cref="TaskFactory"/> that uses the <see cref="FifoTaskScheduler"/> to schedule tasks. |
| | | 12 | | /// </summary> |
| | | 13 | | #if NET5_0_OR_GREATER |
| | | 14 | | [UnsupportedOSPlatform("browser")] |
| | | 15 | | #endif |
| | | 16 | | public sealed class FifoTaskFactory : TaskFactory |
| | | 17 | | { |
| | 1 | 18 | | private static readonly FifoTaskFactory _DefaultTaskFactory = new(); |
| | | 19 | | /// <summary> |
| | | 20 | | /// Gets the default <see cref="FifoTaskFactory"/>. |
| | | 21 | | /// </summary> |
| | 1 | 22 | | public static FifoTaskFactory Default => _DefaultTaskFactory; |
| | | 23 | | /// <summary> |
| | | 24 | | /// Constructs a <see cref="TaskFactory"/> that uses the <see cref="FifoTaskScheduler.Default"/> task scheduler. |
| | | 25 | | /// </summary> |
| | | 26 | | public FifoTaskFactory() |
| | 1 | 27 | | : this(CancellationToken.None, TaskCreationOptions.PreferFairness | TaskCreationOptions.LongRunning | TaskCr |
| | | 28 | | { |
| | 1 | 29 | | } |
| | | 30 | | /// <summary> |
| | | 31 | | /// Initializes a <see cref="FifoTaskFactory"/> instance with the specified configuration. |
| | | 32 | | /// </summary> |
| | | 33 | | /// <param name="cancellationToken">The default <see cref="CancellationToken"/> to use for tasks that are starte |
| | | 34 | | public FifoTaskFactory(CancellationToken cancellationToken) |
| | 1 | 35 | | : this(cancellationToken, TaskCreationOptions.PreferFairness | TaskCreationOptions.LongRunning | TaskCreatio |
| | | 36 | | { |
| | 1 | 37 | | } |
| | | 38 | | /// <summary> |
| | | 39 | | /// Initializes a <see cref="FifoTaskFactory"/> instance with the specified configuration. |
| | | 40 | | /// </summary> |
| | | 41 | | /// <param name="scheduler">The default <see cref="FifoTaskScheduler"/> to use.</param> |
| | | 42 | | public FifoTaskFactory(FifoTaskScheduler scheduler) |
| | 1 | 43 | | : this(CancellationToken.None, TaskCreationOptions.PreferFairness | TaskCreationOptions.LongRunning | TaskCr |
| | | 44 | | { |
| | 1 | 45 | | } |
| | | 46 | | /// <summary> |
| | | 47 | | /// Initializes a <see cref="FifoTaskFactory"/> instance with the specified configuration. |
| | | 48 | | /// </summary> |
| | | 49 | | /// <param name="creationOptions">A set of <see cref="TaskCreationOptions"/> controlling task creation.</param> |
| | | 50 | | /// <param name="continuationOptions">A set of <see cref="TaskContinuationOptions"/> controlling task continuati |
| | | 51 | | public FifoTaskFactory(TaskCreationOptions creationOptions, TaskContinuationOptions continuationOptions) |
| | 1 | 52 | | : this(CancellationToken.None, creationOptions, continuationOptions, FifoTaskScheduler.Default) |
| | | 53 | | { |
| | 1 | 54 | | } |
| | | 55 | | /// <summary> |
| | | 56 | | /// Initializes a <see cref="FifoTaskFactory"/> instance with the specified configuration. |
| | | 57 | | /// </summary> |
| | | 58 | | /// <param name="cancellationToken">The default <see cref="CancellationToken"/> to use for tasks that are starte |
| | | 59 | | /// <param name="creationOptions">A set of <see cref="TaskCreationOptions"/> controlling task creation.</param> |
| | | 60 | | /// <param name="continuationOptions">A set of <see cref="TaskContinuationOptions"/> controlling task continuati |
| | | 61 | | /// <param name="scheduler">The default <see cref="FifoTaskScheduler"/> to use.</param> |
| | | 62 | | [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1068:CancellationToken parameters must come last", |
| | | 63 | | public FifoTaskFactory(CancellationToken cancellationToken, TaskCreationOptions creationOptions, TaskContinuatio |
| | 1 | 64 | | : base(cancellationToken, creationOptions, continuationOptions, scheduler) |
| | | 65 | | { |
| | 1 | 66 | | } |
| | | 67 | | } |
| | | 68 | | #if false |
| | | 69 | | /// <summary> |
| | | 70 | | /// A <see cref="SynchronizationContext"/> that schedules work items on the <see cref="FifoTaskScheduler"/>. |
| | | 71 | | /// </summary> |
| | | 72 | | #if NET5_0_OR_GREATER |
| | | 73 | | [UnsupportedOSPlatform("browser")] |
| | | 74 | | #endif |
| | | 75 | | internal class FifoSynchronizationContext : SynchronizationContext |
| | | 76 | | { |
| | | 77 | | private readonly FifoTaskScheduler _scheduler; |
| | | 78 | | |
| | | 79 | | internal FifoSynchronizationContext(FifoTaskScheduler? scheduler = null) |
| | | 80 | | { |
| | | 81 | | SetWaitNotificationRequired(); |
| | | 82 | | _scheduler = scheduler ?? FifoTaskScheduler.Default; |
| | | 83 | | } |
| | | 84 | | |
| | | 85 | | /// <summary> |
| | | 86 | | /// Synchronously posts a message. |
| | | 87 | | /// </summary> |
| | | 88 | | /// <param name="d">The message to post.</param> |
| | | 89 | | /// <param name="state">The state to give to the post callback.</param> |
| | | 90 | | public override void Send(SendOrPostCallback d, object? state) |
| | | 91 | | { |
| | | 92 | | if (d == null) throw new ArgumentNullException(nameof(d)); |
| | | 93 | | _ = _scheduler.QueueWork(() => d(state)); |
| | | 94 | | } |
| | | 95 | | /// <summary> |
| | | 96 | | /// Posts a message. |
| | | 97 | | /// </summary> |
| | | 98 | | /// <param name="d">The message to post.</param> |
| | | 99 | | /// <param name="state">The state to give to the post callback.</param> |
| | | 100 | | public override void Post(SendOrPostCallback d, object? state) |
| | | 101 | | { |
| | | 102 | | if (d == null) throw new ArgumentNullException(nameof(d)); |
| | | 103 | | _ = _scheduler.QueueWork(() => d(state)); |
| | | 104 | | } |
| | | 105 | | /// <summary> |
| | | 106 | | /// Creates a "copy" of this <see cref="FifoSynchronizationContext"/>, which in this case just returns the singl |
| | | 107 | | /// </summary> |
| | | 108 | | /// <returns>The same singleton <see cref="FifoSynchronizationContext"/> on which we were called.</returns> |
| | | 109 | | public override SynchronizationContext CreateCopy() |
| | | 110 | | { |
| | | 111 | | return this; |
| | | 112 | | } |
| | | 113 | | } |
| | | 114 | | #endif |
| | | 115 | | /// <summary> |
| | | 116 | | /// A class that holds arguments for the task inlined event arguments. |
| | | 117 | | /// </summary> |
| | | 118 | | public class TaskInlinedEventArgs : EventArgs |
| | | 119 | | { |
| | | 120 | | /// <summary> |
| | | 121 | | /// Constructs a task inlined arguments. |
| | | 122 | | /// </summary> |
| | | 123 | | public TaskInlinedEventArgs() |
| | | 124 | | { |
| | | 125 | | } |
| | | 126 | | } |
| | | 127 | | /// <summary> |
| | | 128 | | /// A worker which contains a thread and various other objects needed to use the thread. Disposes of itself when th |
| | | 129 | | /// </summary> |
| | | 130 | | #if NET5_0_OR_GREATER |
| | | 131 | | [UnsupportedOSPlatform("browser")] |
| | | 132 | | #endif |
| | | 133 | | internal sealed class FifoWorker : IntrusiveSinglyLinkedListNode, IDisposable |
| | | 134 | | { |
| | | 135 | | private static long _SlowestInvocation; // interlocked |
| | | 136 | | |
| | | 137 | | private readonly FifoTaskScheduler _scheduler; |
| | | 138 | | private readonly string _schedulerName; |
| | | 139 | | private readonly string _id; |
| | | 140 | | private readonly Thread _thread; |
| | | 141 | | private readonly ManualResetEvent _wakeThread = new(false); |
| | | 142 | | private readonly ManualResetEvent _allowDisposal = new(false); |
| | | 143 | | private Action? _actionToPerform; // interlocked |
| | | 144 | | private long _invokeTicks; // interlocked |
| | | 145 | | private int _stop; // interlocked |
| | | 146 | | |
| | | 147 | | public static FifoWorker Start(FifoTaskScheduler scheduler, string id, ThreadPriority priority) |
| | | 148 | | { |
| | | 149 | | FifoWorker ret = new(scheduler, id, priority); |
| | | 150 | | ret.Start(); |
| | | 151 | | return ret; |
| | | 152 | | } |
| | | 153 | | private FifoWorker(FifoTaskScheduler scheduler, string id, ThreadPriority priority) |
| | | 154 | | { |
| | | 155 | | _scheduler = scheduler; |
| | | 156 | | _schedulerName = scheduler.Name; |
| | | 157 | | _id = id; |
| | | 158 | | // start the thread, it should block immediately until a work unit is ready |
| | | 159 | | _thread = new(new ThreadStart(WorkerFunc)) { |
| | | 160 | | Name = id, |
| | | 161 | | IsBackground = true, |
| | | 162 | | Priority = priority |
| | | 163 | | }; |
| | | 164 | | } |
| | | 165 | | private void Start() |
| | | 166 | | { |
| | | 167 | | _thread.Start(); |
| | | 168 | | _scheduler.SchedulerWorkersCreated?.IncrementRaw(); |
| | | 169 | | } |
| | | 170 | | #if DEBUG |
| | | 171 | | private readonly string fStackAtConstruction = new StackTrace().ToString(); |
| | | 172 | | ~FifoWorker() |
| | | 173 | | { |
| | | 174 | | Debug.Fail($"{nameof(FifoWorker)} '{_schedulerName}:{_id}' instance not disposed! Constructed at: {fStackAt |
| | | 175 | | Dispose(); |
| | | 176 | | } |
| | | 177 | | #endif |
| | | 178 | | |
| | | 179 | | public void Dispose() |
| | | 180 | | { |
| | | 181 | | // dispose of the events |
| | | 182 | | _wakeThread.Dispose(); |
| | | 183 | | _allowDisposal.Dispose(); |
| | | 184 | | #if DEBUG |
| | | 185 | | // suppress finalization |
| | | 186 | | System.GC.SuppressFinalize(this); |
| | | 187 | | #endif |
| | | 188 | | } |
| | | 189 | | |
| | | 190 | | /// <summary> |
| | | 191 | | /// Gets whether or not this worker is currently executing a job. |
| | | 192 | | /// </summary> |
| | | 193 | | internal bool IsBusy => _actionToPerform != null; |
| | | 194 | | |
| | | 195 | | /// <summary> |
| | | 196 | | /// Schedules the specified delegate on this worker's thread and returns <b>true</b>, or returns <b>false</b> if |
| | | 197 | | /// </summary> |
| | | 198 | | /// <param name="action">The action to attempt to carry out on this worker.</param> |
| | | 199 | | internal void Invoke(Action action) |
| | | 200 | | { |
| | | 201 | | // are we already stopped? |
| | | 202 | | if (_stop != 0 || _scheduler.Stopping) |
| | | 203 | | { |
| | | 204 | | throw new InvalidOperationException("The worker has already been stopped!"); |
| | | 205 | | } |
| | | 206 | | // try to put in this work--if there is something already there, we must be busy! |
| | | 207 | | if (Interlocked.CompareExchange(ref _actionToPerform, action, null) != null) |
| | | 208 | | { |
| | | 209 | | // the worker was busy so we couldn't marshal the action to it! |
| | | 210 | | throw new InvalidOperationException("Worker thread already in use!"); |
| | | 211 | | } |
| | | 212 | | // start the timer |
| | | 213 | | Interlocked.Exchange(ref _invokeTicks, FifoTaskScheduler.Ticks); |
| | | 214 | | // signal the thread to begin the work |
| | | 215 | | _wakeThread.Set(); |
| | | 216 | | // we successfully issued the work request |
| | | 217 | | } |
| | | 218 | | /// <summary> |
| | | 219 | | /// Tells the thread to stop and exit. |
| | | 220 | | /// </summary> |
| | | 221 | | internal void Stop() |
| | | 222 | | { |
| | | 223 | | // record when we invoked the stop command |
| | | 224 | | Interlocked.Exchange(ref _invokeTicks, FifoTaskScheduler.Ticks); |
| | | 225 | | // mark for stopping |
| | | 226 | | Interlocked.Exchange(ref _stop, 1); |
| | | 227 | | // worker has retired! |
| | | 228 | | _scheduler.SchedulerWorkersRetired?.IncrementRaw(); |
| | | 229 | | FifoTaskScheduler.Logger.Filter("StartStop", AmbientLogLevel.Debug)?.Log(new { Action = "RetireWorker", Work |
| | | 230 | | // wake thread so it can exit gracefully |
| | | 231 | | _wakeThread.Set(); |
| | | 232 | | // tell the thread it can dispose and exit |
| | | 233 | | _allowDisposal.Set(); |
| | | 234 | | } |
| | | 235 | | |
| | | 236 | | internal static bool IsWorkerInternalMethod(MethodBase? method) |
| | | 237 | | { |
| | | 238 | | if (method == null || method.DeclaringType != typeof(FifoWorker)) return false; |
| | | 239 | | return !method.IsPublic; |
| | | 240 | | } |
| | | 241 | | |
| | | 242 | | [System.Diagnostics.CodeAnalysis.SuppressMessage("Maintainability", "CA1508:Avoid dead conditional code", Justif |
| | | 243 | | private void WorkerFunc() |
| | | 244 | | { |
| | | 245 | | try |
| | | 246 | | { |
| | | 247 | | long maxInvokeTicks = 0; |
| | | 248 | | _scheduler.SchedulerWorkers?.IncrementRaw(); |
| | | 249 | | try |
| | | 250 | | { |
| | | 251 | | FifoTaskScheduler.Logger.Filter("ThreadStartStop", AmbientLogLevel.Debug)?.Log(new { Action = "Start |
| | | 252 | | long startTicks = FifoTaskScheduler.Ticks; |
| | | 253 | | long completionTicks = startTicks; |
| | | 254 | | // loop until we're told to stop |
| | | 255 | | while (_stop == 0 && !_scheduler.Stopping) |
| | | 256 | | { |
| | | 257 | | startTicks = FifoTaskScheduler.Ticks; |
| | | 258 | | completionTicks = startTicks; |
| | | 259 | | // wait for the wake thread event to be signalled so we can start some work |
| | | 260 | | FifoTaskScheduler.WaitForWork(_wakeThread); |
| | | 261 | | // stop now? |
| | | 262 | | if (_stop != 0 || _scheduler.Stopping) |
| | | 263 | | { |
| | | 264 | | break; |
| | | 265 | | } |
| | | 266 | | // record the start time |
| | | 267 | | startTicks = FifoTaskScheduler.Ticks; |
| | | 268 | | // NO work to execute? (just in case--I don't think this can ever really happen) |
| | | 269 | | if (_actionToPerform == null) |
| | | 270 | | { |
| | | 271 | | // nothing to do, so we're done |
| | | 272 | | completionTicks = FifoTaskScheduler.Ticks; |
| | | 273 | | } |
| | | 274 | | else |
| | | 275 | | { |
| | | 276 | | _scheduler.SchedulerBusyWorkers?.IncrementRaw(); |
| | | 277 | | try |
| | | 278 | | { |
| | | 279 | | // perform the work (handling any uncaught exception) |
| | | 280 | | _scheduler.ExecuteAction(_actionToPerform); |
| | | 281 | | } |
| | | 282 | | finally |
| | | 283 | | { |
| | | 284 | | _scheduler.SchedulerBusyWorkers?.DecrementRaw(); |
| | | 285 | | // mark the time |
| | | 286 | | completionTicks = FifoTaskScheduler.Ticks; |
| | | 287 | | } |
| | | 288 | | } |
| | | 289 | | // finish work in success case--we're done with the work, so get rid of it so we're ready for th |
| | | 290 | | Interlocked.Exchange(ref _actionToPerform, null); |
| | | 291 | | // not stopping? |
| | | 292 | | if (_stop == 0 && !_scheduler.Stopping) |
| | | 293 | | { |
| | | 294 | | // release the worker back to the ready list |
| | | 295 | | _scheduler.OnWorkerReady(this); |
| | | 296 | | } |
| | | 297 | | // record statistics |
| | | 298 | | long invokeTime = _invokeTicks; |
| | | 299 | | // ignore how long it took if we never got invoked |
| | | 300 | | if (invokeTime > 0) |
| | | 301 | | { |
| | | 302 | | long invokeTicks = startTicks - invokeTime; |
| | | 303 | | long executionTicks = completionTicks - startTicks; |
| | | 304 | | if (invokeTicks > maxInvokeTicks) |
| | | 305 | | { |
| | | 306 | | maxInvokeTicks = invokeTicks; |
| | | 307 | | InterlockedUtilities.TryOptomisticMax(ref _SlowestInvocation, invokeTicks); |
| | | 308 | | _scheduler.SchedulerSlowestInvocationMilliseconds?.SetValue(_SlowestInvocation * 1000 / |
| | | 309 | | } |
| | | 310 | | _scheduler.SchedulerInvocationTime?.AddRaw(invokeTicks); |
| | | 311 | | } |
| | | 312 | | } |
| | | 313 | | FifoTaskScheduler.Logger.Filter("ThreadStartStop", AmbientLogLevel.Debug)?.Log(new { Action = "ExitW |
| | | 314 | | } |
| | | 315 | | finally |
| | | 316 | | { |
| | | 317 | | _scheduler.SchedulerWorkers?.DecrementRaw(); |
| | | 318 | | } |
| | | 319 | | } |
| | | 320 | | finally |
| | | 321 | | { |
| | | 322 | | // wait for up to one second for the stopper to be done accessing us |
| | | 323 | | _allowDisposal.WaitOne(1000); |
| | | 324 | | Dispose(); |
| | | 325 | | } |
| | | 326 | | } |
| | | 327 | | } |
| | | 328 | | /// <summary> |
| | | 329 | | /// A <see cref="TaskScheduler"/> that is high performance and runs tasks in first-in-first-out order. |
| | | 330 | | /// </summary> |
| | | 331 | | #if NET5_0_OR_GREATER |
| | | 332 | | [UnsupportedOSPlatform("browser")] |
| | | 333 | | #endif |
| | | 334 | | public sealed class FifoTaskScheduler : TaskScheduler, IDisposable |
| | | 335 | | { |
| | | 336 | | private static readonly AmbientService<IAmbientStatistics> _AmbientStatistics = Ambient.GetService<IAmbientStati |
| | | 337 | | internal static readonly AmbientLogger<FifoTaskScheduler> Logger = new(); |
| | | 338 | | |
| | | 339 | | private static readonly int LogicalCpuCount = GetProcessorCount(); |
| | | 340 | | private static readonly int MaxWorkerThreads = LogicalCpuCount * MaxThreadsPerLogicalCpu; |
| | | 341 | | private static readonly int HighThreadCountWarningEnvironmentTicks = (int)TimeSpan.FromHours(1).Ticks; |
| | | 342 | | private static readonly float MinAddThreadsCpuUsage = Math.Max(0.95f, 1.0f - (0.5f / LogicalCpuCount)); |
| | | 343 | | private static readonly CpuMonitor CpuMonitor = new(1000); |
| | | 344 | | private static readonly ConcurrentHashSet<FifoTaskScheduler> Schedulers = new(); |
| | | 345 | | |
| | | 346 | | private const float MaxCpuUsage = 0.97f; |
| | | 347 | | #if DEBUG |
| | | 348 | | private const int BufferThreadCount = 2; |
| | | 349 | | private static readonly int RetireCheckAfterCreationTickCount = (int)TimeSpan.FromSeconds(60).Ticks; |
| | | 350 | | private static readonly int RetireCheckFastestRetirementFrequencyTickCount = (int)TimeSpan.FromSeconds(3).Ticks; |
| | | 351 | | private const int MaxThreadsPerLogicalCpu = 5; |
| | | 352 | | |
| | | 353 | | private readonly bool _executeDisposalCheck; |
| | | 354 | | #else |
| | | 355 | | private const int BufferThreadsPerCpu = 2; |
| | | 356 | | private readonly static int BufferThreadCount = LogicalCpuCount * BufferThreadsPerCpu; |
| | | 357 | | private static readonly int RetireCheckAfterCreationTickCount = (int)TimeSpan.FromMinutes(5).Ticks; |
| | | 358 | | private static readonly int RetireCheckFastestRetirementFrequencyTickCount = (int)TimeSpan.FromSeconds(60).Ticks |
| | | 359 | | private const int MaxThreadsPerLogicalCpu = 50; |
| | | 360 | | #endif |
| | | 361 | | |
| | | 362 | | // initialize this here to be sure all the above values have been set (it uses many of them) |
| | | 363 | | private static readonly FifoTaskScheduler DefaultTaskScheduler = FifoTaskScheduler.Start("FIFO Default", 0, 0, T |
| | | 364 | | |
| | | 365 | | /// <summary> |
| | | 366 | | /// Gets the default <see cref="FifoTaskScheduler"/>, one with normal priorities. |
| | | 367 | | /// </summary> |
| | | 368 | | public static new FifoTaskScheduler Default => DefaultTaskScheduler; |
| | | 369 | | |
| | | 370 | | internal readonly IAmbientStatistic? SchedulerInvocations; |
| | | 371 | | internal readonly IAmbientStatistic? SchedulerInvocationTime; |
| | | 372 | | internal readonly IAmbientStatistic? SchedulerWorkersCreated; |
| | | 373 | | internal readonly IAmbientStatistic? SchedulerWorkersRetired; |
| | | 374 | | internal readonly IAmbientStatistic? SchedulerInlineExecutions; |
| | | 375 | | internal readonly IAmbientStatistic? SchedulerWorkers; |
| | | 376 | | internal readonly IAmbientStatistic? SchedulerBusyWorkers; |
| | | 377 | | internal readonly IAmbientStatistic? SchedulerWorkersHighWaterMark; |
| | | 378 | | internal readonly IAmbientStatistic? SchedulerSlowestInvocationMilliseconds; |
| | | 379 | | |
| | | 380 | | private readonly IAmbientStatistics? _statistics; |
| | | 381 | | private readonly string _schedulerName; |
| | | 382 | | private readonly ThreadPriority _schedulerThreadPriority; |
| | | 383 | | private readonly int _schedulerMasterFrequencyMilliseconds; |
| | | 384 | | private readonly int _bufferWorkerThreads; |
| | | 385 | | private readonly int _maxWorkerThreads; |
| | | 386 | | private readonly bool _testMode; |
| | | 387 | | private readonly Thread _schedulerMasterThread; |
| | | 388 | | private readonly ManualResetEvent _wakeSchedulerMasterThread = new(false); // controls the master thread waking |
| | | 389 | | private readonly InterlockedSinglyLinkedList<FifoWorker> _readyWorkerList = new(); |
| | | 390 | | // everything from here down is interlocked |
| | | 391 | | private int _reset; // triggers a one-time reset of the thread count |
| | | 392 | | private int _stopMasterThread; // stops the master thread (shuts down the sched |
| | | 393 | | private int _workerId; // an incrementing worker id used to name the wo |
| | | 394 | | private int _busyWorkers; // the number of busy workers (interlocked) |
| | | 395 | | private int _workers; // the total number of workers |
| | | 396 | | private long _peakConcurrentUsageSinceLastRetirementCheck; // the peak concurrent usage since the last redu |
| | | 397 | | private long _workersHighWaterMark; // the most workers we've ever seen (interlocked |
| | | 398 | | private int _highThreadsWarningTickCount; // the last time we warned about too many thread |
| | | 399 | | private int _lastInlineExecutionTicks; // the last time we had to execute something inl |
| | | 400 | | private long _lastScaleUpTime; // keeps track of the last time a scale up |
| | | 401 | | private long _lastScaleDownTime; // keeps track of the last time a scale down |
| | | 402 | | private long _lastResetTime; // keeps track of the last time a reset happened |
| | | 403 | | |
| | | 404 | | /// <summary> |
| | | 405 | | /// An event that notifies scubscribers whenever an exception is thrown and not handled by the specified non-Tas |
| | | 406 | | /// </summary> |
| | | 407 | | public static event EventHandler<UnobservedTaskExceptionEventArgs>? UnhandledException; |
| | | 408 | | /// <summary> |
| | | 409 | | /// An event that notifies scubscribers whenever a task is inlined due to all threads currently being busy. |
| | | 410 | | /// </summary> |
| | | 411 | | public static event EventHandler<TaskInlinedEventArgs>? TaskInlined; |
| | | 412 | | |
| | | 413 | | internal void RaiseUnhandledException(Exception ex) |
| | | 414 | | { |
| | | 415 | | UnhandledException?.Invoke(this, new UnobservedTaskExceptionEventArgs((ex as AggregateException) ?? new Aggr |
| | | 416 | | } |
| | | 417 | | |
| | | 418 | | internal bool Stopping => _stopMasterThread != 0; |
| | | 419 | | /// <summary> |
| | | 420 | | /// Gets the <see cref="DateTime"/> of the completion of the last scale up. |
| | | 421 | | /// </summary> |
| | | 422 | | public DateTime LastScaleUp => new(_lastScaleUpTime); |
| | | 423 | | /// <summary> |
| | | 424 | | /// Gets the <see cref="DateTime"/> of the completion of the last scale down. |
| | | 425 | | /// </summary> |
| | | 426 | | public DateTime LastScaleDown => new(_lastScaleDownTime); |
| | | 427 | | /// <summary> |
| | | 428 | | /// Gets the <see cref="DateTime"/> of the completion of the last reset. |
| | | 429 | | /// </summary> |
| | | 430 | | public DateTime LastResetTime => new(_lastResetTime); |
| | | 431 | | /// <summary> |
| | | 432 | | /// Gets the current number of workers. |
| | | 433 | | /// </summary> |
| | | 434 | | public int Workers => _workers; |
| | | 435 | | /// <summary> |
| | | 436 | | /// Gets the number of currently busy workers. |
| | | 437 | | /// </summary> |
| | | 438 | | public int BusyWorkers => _busyWorkers; |
| | | 439 | | /// <summary> |
| | | 440 | | /// Gets the number of currently ready workers. |
| | | 441 | | /// </summary> |
| | | 442 | | public int ReadyWorkers => _readyWorkerList.Count; |
| | | 443 | | |
| | | 444 | | /// <summary> |
| | | 445 | | /// Stops the all the task schedulers by disposing of all of them. |
| | | 446 | | /// </summary> |
| | | 447 | | public static void Stop() |
| | | 448 | | { |
| | | 449 | | foreach (FifoTaskScheduler scheduler in Schedulers) |
| | | 450 | | { |
| | | 451 | | scheduler.Dispose(); |
| | | 452 | | } |
| | | 453 | | } |
| | | 454 | | |
| | | 455 | | /// <summary> |
| | | 456 | | /// Gets the name of the scheduler. |
| | | 457 | | /// </summary> |
| | | 458 | | public string Name => _schedulerName; |
| | | 459 | | |
| | | 460 | | /// <summary> |
| | | 461 | | /// Gets the ticks used internally for performance tracking. |
| | | 462 | | /// </summary> |
| | | 463 | | public static long Ticks => AmbientStopwatch.GetTimestamp(); |
| | | 464 | | |
| | | 465 | | /// <summary> |
| | | 466 | | /// Gets the number of ticks per second used internally for performance tracking. |
| | | 467 | | /// </summary> |
| | | 468 | | public static long TicksPerSecond => AmbientStopwatch.Frequency; |
| | | 469 | | |
| | | 470 | | [ExcludeFromCodeCoverage] // I've seen this throw an exception, but I have no idea how that's possible, let al |
| | | 471 | | private static int GetProcessorCount() |
| | | 472 | | { |
| | | 473 | | try |
| | | 474 | | { |
| | | 475 | | return Environment.ProcessorCount; |
| | | 476 | | } |
| | | 477 | | catch |
| | | 478 | | { |
| | | 479 | | // default to sixteen if we can't query |
| | | 480 | | return 16; |
| | | 481 | | } |
| | | 482 | | } |
| | | 483 | | /// <summary> |
| | | 484 | | /// Starts a new <see cref="FifoTaskScheduler"/> with the specified configuration. |
| | | 485 | | /// </summary> |
| | | 486 | | /// <param name="schedulerName">The name of the task scheduler (used in logging and exceptions).</param> |
| | | 487 | | /// <param name="bufferThreadCount">The number of threads to start with and to keep as a buffer after resetting. |
| | | 488 | | /// <param name="maxThreads">The maximum number of threads to use, or zero to let the system decide.</param> |
| | | 489 | | /// <param name="priority">The <see cref="ThreadPriority"/> for the threads that will be used ot execute the tas |
| | | 490 | | /// <param name="executeDisposalCheck">Whether or not to verify that the instance is properly disposed. Default |
| | | 491 | | /// <param name="statistics">An optional <see cref="IAmbientStatistics"/> to use for reporting statistics, if no |
| | | 492 | | /// <returns>A new <see cref="FifoTaskScheduler"/> instance.</returns> |
| | | 493 | | internal static FifoTaskScheduler Start(string schedulerName, int bufferThreadCount, int maxThreads, ThreadPrior |
| | | 494 | | { |
| | | 495 | | FifoTaskScheduler ret = new(schedulerName, bufferThreadCount, maxThreads, priority, executeDisposalCheck, st |
| | | 496 | | ret.Start(); |
| | | 497 | | return ret; |
| | | 498 | | } |
| | | 499 | | private FifoTaskScheduler (string scheduler, int bufferThreadCount, int maxThreads, ThreadPriority priority, boo |
| | | 500 | | : this(scheduler, bufferThreadCount, maxThreads, priority, statistics) |
| | | 501 | | { |
| | | 502 | | #if DEBUG |
| | | 503 | | _executeDisposalCheck = executeDisposalCheck; |
| | | 504 | | #endif |
| | | 505 | | } |
| | | 506 | | |
| | | 507 | | /// <summary> |
| | | 508 | | /// Starts a new <see cref="FifoTaskScheduler"/> with the specified configuration. |
| | | 509 | | /// </summary> |
| | | 510 | | /// <param name="schedulerName">The name of the task scheduler (used in logging and exceptions).</param> |
| | | 511 | | /// <param name="bufferThreadCount">The number of threads to start with and to keep as a buffer after resetting. |
| | | 512 | | /// <param name="maxThreads">The maximum number of threads to use, or zero to let the system decide. Defaults t |
| | | 513 | | /// <param name="priority">The <see cref="ThreadPriority"/> for the threads that will be used ot execute the tas |
| | | 514 | | /// <returns>A new <see cref="FifoTaskScheduler"/> instance.</returns> |
| | | 515 | | public static FifoTaskScheduler Start(string schedulerName, int bufferThreadCount = 0, int maxThreads = 0, Threa |
| | | 516 | | { |
| | | 517 | | FifoTaskScheduler ret = new(schedulerName, bufferThreadCount, maxThreads, priority); |
| | | 518 | | ret.Start(); |
| | | 519 | | return ret; |
| | | 520 | | } |
| | | 521 | | /// <summary> |
| | | 522 | | /// Starts a new <see cref="FifoTaskScheduler"/> in test mode with the specified configuration. |
| | | 523 | | /// </summary> |
| | | 524 | | /// <param name="schedulerName">The name of the task scheduler (used in logging and exceptions).</param> |
| | | 525 | | /// <param name="bufferThreadCount">The number of threads to start with and to keep as a buffer after resetting. |
| | | 526 | | /// <param name="maxThreads">The maximum number of threads to use, or zero to let the system decide.</param> |
| | | 527 | | /// <param name="schedulerMasterFrequencyMilliseconds">How many milliseconds to wait each time around the master |
| | | 528 | | /// <param name="statistics">An optional <see cref="IAmbientStatistics"/> to use for reporting statistics, if no |
| | | 529 | | /// <returns>A new <see cref="FifoTaskScheduler"/> instance.</returns> |
| | | 530 | | internal static FifoTaskScheduler Start(string schedulerName, int bufferThreadCount, int maxThreads, int schedul |
| | | 531 | | { |
| | | 532 | | FifoTaskScheduler ret = new(schedulerName, bufferThreadCount, maxThreads, ThreadPriority.Normal, statistics, |
| | | 533 | | ret.Start(); |
| | | 534 | | return ret; |
| | | 535 | | } |
| | | 536 | | private FifoTaskScheduler(string schedulerName, int bufferThreadCount = 0, int maxThreads = 0, ThreadPriority pr |
| | | 537 | | { |
| | | 538 | | // save the scheduler name and priority |
| | | 539 | | _statistics = statistics ?? _AmbientStatistics.Local; |
| | | 540 | | _schedulerName = schedulerName; |
| | | 541 | | _schedulerThreadPriority = priority; |
| | | 542 | | _schedulerMasterFrequencyMilliseconds = schedulerMasterFrequencyMilliseconds; |
| | | 543 | | _bufferWorkerThreads = (bufferThreadCount == 0) ? BufferThreadCount : bufferThreadCount; |
| | | 544 | | _maxWorkerThreads = (maxThreads == 0) ? MaxWorkerThreads : maxThreads; |
| | | 545 | | _testMode = testMode; |
| | | 546 | | _lastResetTime = _lastScaleDownTime = _lastScaleUpTime = AmbientClock.UtcNow.AddSeconds(-1).Ticks; |
| | | 547 | | |
| | | 548 | | SchedulerInvocations = _statistics?.GetOrAddStatistic(AmbientStatisticType.Cumulative, $"{nameof(SchedulerIn |
| | | 549 | | SchedulerInvocationTime = _statistics?.GetOrAddTimeBasedStatistic(AmbientStatisticType.Cumulative, $"{nameof |
| | | 550 | | SchedulerWorkersCreated = _statistics?.GetOrAddStatistic(AmbientStatisticType.Cumulative, $"{nameof(Schedule |
| | | 551 | | SchedulerWorkersRetired = _statistics?.GetOrAddStatistic(AmbientStatisticType.Cumulative, $"{nameof(Schedule |
| | | 552 | | SchedulerInlineExecutions = _statistics?.GetOrAddStatistic(AmbientStatisticType.Cumulative, $"{nameof(Schedu |
| | | 553 | | SchedulerWorkers = _statistics?.GetOrAddStatistic(AmbientStatisticType.Raw, $"{nameof(SchedulerWorkers)}:{sc |
| | | 554 | | SchedulerBusyWorkers = _statistics?.GetOrAddStatistic(AmbientStatisticType.Raw, $"{nameof(SchedulerBusyWorke |
| | | 555 | | SchedulerWorkersHighWaterMark = _statistics?.GetOrAddStatistic(AmbientStatisticType.Max, $"{nameof(Scheduler |
| | | 556 | | SchedulerSlowestInvocationMilliseconds = _statistics?.GetOrAddStatistic(AmbientStatisticType.Max, $"{nameof( |
| | | 557 | | |
| | | 558 | | _schedulerMasterThread = new(new ThreadStart(SchedulerMaster)) { |
| | | 559 | | Name = "High Performance FIFO Shceduler '" + schedulerName + "' Master", |
| | | 560 | | IsBackground = true, |
| | | 561 | | Priority = (priority >= ThreadPriority.Highest) ? priority : (priority + 1) |
| | | 562 | | }; |
| | | 563 | | } |
| | | 564 | | private void Start() |
| | | 565 | | { |
| | | 566 | | // initialize at least one worker immediately |
| | | 567 | | for (int i = 0; i < Math.Min(1, _bufferWorkerThreads); ++i) |
| | | 568 | | { |
| | | 569 | | #pragma warning disable CA2000 // Dispose objects before losing scope This is put into a collection and disposed later |
| | | 570 | | FifoWorker worker = CreateWorker(); |
| | | 571 | | #pragma warning restore CA2000 // Dispose objects before losing scope |
| | | 572 | | Debug.Assert(!worker.IsBusy); |
| | | 573 | | _readyWorkerList.Push(worker); |
| | | 574 | | } |
| | | 575 | | _workersHighWaterMark = _readyWorkerList.Count; |
| | | 576 | | SchedulerWorkersHighWaterMark?.SetValue(_readyWorkerList.Count); |
| | | 577 | | _schedulerMasterThread.Start(); |
| | | 578 | | Schedulers.Add(this); |
| | | 579 | | } |
| | | 580 | | |
| | | 581 | | #if DEBUG |
| | | 582 | | private readonly string fStackAtConstruction = new StackTrace().ToString(); |
| | | 583 | | ~FifoTaskScheduler() |
| | | 584 | | { |
| | | 585 | | if (_executeDisposalCheck) |
| | | 586 | | { |
| | | 587 | | Debug.Fail($"Failed to dispose/close {nameof(FifoTaskScheduler)} {_schedulerName}: Stack at construction |
| | | 588 | | } |
| | | 589 | | |
| | | 590 | | Dispose(); |
| | | 591 | | } |
| | | 592 | | #endif |
| | | 593 | | /// <summary> |
| | | 594 | | /// Disposes of the instance. |
| | | 595 | | /// </summary> |
| | | 596 | | public void Dispose() |
| | | 597 | | { |
| | | 598 | | // signal the master thread to stop |
| | | 599 | | Interlocked.Exchange(ref _stopMasterThread, 1); |
| | | 600 | | _wakeSchedulerMasterThread.Set(); |
| | | 601 | | // wait for the scheduler master thread to recieve the message and shut down |
| | | 602 | | _schedulerMasterThread.Join(); |
| | | 603 | | // retire all the the workers (now that the master thread has stopped, it shouldn't be able to start any mor |
| | | 604 | | while (RetireOneWorker()) { } |
| | | 605 | | // if there are any busy workers, they will just stop and dispose of themselves when they see that the sched |
| | | 606 | | // remove us from the master list of schedulers |
| | | 607 | | Schedulers.Remove(this); |
| | | 608 | | _wakeSchedulerMasterThread.Dispose(); |
| | | 609 | | |
| | | 610 | | SchedulerInvocations?.Dispose(); |
| | | 611 | | SchedulerInvocationTime?.Dispose(); |
| | | 612 | | SchedulerWorkersCreated?.Dispose(); |
| | | 613 | | SchedulerWorkersRetired?.Dispose(); |
| | | 614 | | SchedulerInlineExecutions?.Dispose(); |
| | | 615 | | SchedulerWorkers?.Dispose(); |
| | | 616 | | SchedulerBusyWorkers?.Dispose(); |
| | | 617 | | SchedulerWorkersHighWaterMark?.Dispose(); |
| | | 618 | | SchedulerSlowestInvocationMilliseconds?.Dispose(); |
| | | 619 | | |
| | | 620 | | #if DEBUG |
| | | 621 | | // we're being disposed properly, so no need to call the finalizer |
| | | 622 | | GC.SuppressFinalize(this); |
| | | 623 | | #endif |
| | | 624 | | } |
| | | 625 | | |
| | | 626 | | private string ThreadName(int thread) |
| | | 627 | | { |
| | | 628 | | return $"High Performance FIFO Task Scheduler '{_schedulerName}' Thread {thread + 1}"; |
| | | 629 | | } |
| | | 630 | | |
| | | 631 | | internal static void WaitForWork(ManualResetEvent wakeWorkerThreadEvent) |
| | | 632 | | { |
| | | 633 | | // wait (forever) for an operation or a stop |
| | | 634 | | wakeWorkerThreadEvent.WaitOne(); |
| | | 635 | | // reset the event so we're ready to go again |
| | | 636 | | wakeWorkerThreadEvent.Reset(); |
| | | 637 | | } |
| | | 638 | | |
| | | 639 | | internal FifoWorker CreateWorker() |
| | | 640 | | { |
| | | 641 | | int id = Interlocked.Increment(ref _workerId); |
| | | 642 | | // initialize the worker (starts their threads) |
| | | 643 | | FifoWorker worker = FifoWorker.Start(this, ThreadName(id), _schedulerThreadPriority); |
| | | 644 | | Interlocked.Increment(ref _workers); |
| | | 645 | | // update the high water mark if needed |
| | | 646 | | InterlockedUtilities.TryOptomisticMax(ref _workersHighWaterMark, _workers); |
| | | 647 | | SchedulerWorkersHighWaterMark?.SetValue(_workersHighWaterMark); |
| | | 648 | | return worker; |
| | | 649 | | } |
| | | 650 | | |
| | | 651 | | private static int TimeElapsed(int startTime, int endTime) |
| | | 652 | | { |
| | | 653 | | unchecked |
| | | 654 | | { |
| | | 655 | | return endTime - startTime; |
| | | 656 | | } |
| | | 657 | | } |
| | | 658 | | |
| | | 659 | | /// <summary> |
| | | 660 | | /// Tells the scheduler master thread to reset because we've just finished a massively parallel operation has fi |
| | | 661 | | /// </summary> |
| | | 662 | | public void Reset() |
| | | 663 | | { |
| | | 664 | | // trigger reset |
| | | 665 | | Interlocked.Exchange(ref _reset, 1); |
| | | 666 | | // wake up the master thread so it does it ASAP |
| | | 667 | | _wakeSchedulerMasterThread.Set(); |
| | | 668 | | } |
| | | 669 | | |
| | | 670 | | //[System.Diagnostics.CodeAnalysis.SuppressMessage("Maintainability", "CA1508:Avoid dead conditional code", Just |
| | | 671 | | //[System.Diagnostics.CodeAnalysis.SuppressMessage("Reliability", "CA2000:Dispose objects before losing scope", |
| | | 672 | | private void SchedulerMaster() |
| | | 673 | | { |
| | | 674 | | ExecuteWithCatchAndLog(() => |
| | | 675 | | { |
| | | 676 | | int lastRetirementTicks = Environment.TickCount; |
| | | 677 | | int lastCreationTicks = Environment.TickCount; |
| | | 678 | | ManualResetEvent wakeSchedulerMasterThread = _wakeSchedulerMasterThread; |
| | | 679 | | // loop forever (we're a background thread, so if the process exits, no problem!) |
| | | 680 | | while (_stopMasterThread == 0) |
| | | 681 | | { |
| | | 682 | | ExecuteWithCatchAndLog(() => |
| | | 683 | | { |
| | | 684 | | // sleep for up to one second or until we are awakened |
| | | 685 | | if (wakeSchedulerMasterThread.WaitOne(_schedulerMasterFrequencyMilliseconds)) |
| | | 686 | | { |
| | | 687 | | wakeSchedulerMasterThread.Reset(); |
| | | 688 | | } |
| | | 689 | | // have we just been disposed? |
| | | 690 | | if (_stopMasterThread != 0) return; |
| | | 691 | | // calculate how long it's been since various events |
| | | 692 | | int ticksNow = Environment.TickCount; |
| | | 693 | | int ticksSinceInlineExecution = TimeElapsed(_lastInlineExecutionTicks, ticksNow); |
| | | 694 | | int ticksSinceCreation = TimeElapsed(lastCreationTicks, ticksNow); |
| | | 695 | | int ticksSinceRetirement = TimeElapsed(lastRetirementTicks, ticksNow); |
| | | 696 | | // do we need to add more workers? |
| | | 697 | | int totalWorkers = _workers; |
| | | 698 | | int readyWorkers = _readyWorkerList.Count; |
| | | 699 | | int busyWorkers = _busyWorkers; |
| | | 700 | | // were we explicitly asked to reset the scheduler by retiring threads? |
| | | 701 | | if (_reset != 0) |
| | | 702 | | { |
| | | 703 | | while (_readyWorkerList.Count > _bufferWorkerThreads) |
| | | 704 | | { |
| | | 705 | | // retire one worker--did it turn out to be busy? |
| | | 706 | | if (!RetireOneWorker()) |
| | | 707 | | { |
| | | 708 | | // bail out now--there must have been a surge in work just when we were told to rese |
| | | 709 | | break; |
| | | 710 | | } |
| | | 711 | | } |
| | | 712 | | Interlocked.Exchange(ref _reset, 0); |
| | | 713 | | FifoTaskScheduler.Logger.Filter("Reset", AmbientLogLevel.Debug)?.Log( new { Action = "Reset" |
| | | 714 | | // record that we retired threads just now |
| | | 715 | | lastRetirementTicks = Environment.TickCount; |
| | | 716 | | // record that we just finished a reset |
| | | 717 | | Interlocked.Exchange(ref _lastResetTime, AmbientClock.UtcNow.Ticks); |
| | | 718 | | } |
| | | 719 | | else if (readyWorkers <= _bufferWorkerThreads) |
| | | 720 | | { |
| | | 721 | | float recentCpuUsage = CpuMonitor.RecentUsage; |
| | | 722 | | // too many workers already, or CPU too high? (if the CPU is too high, we risk starving int |
| | | 723 | | if (totalWorkers > _maxWorkerThreads || recentCpuUsage > MaxCpuUsage) |
| | | 724 | | { |
| | | 725 | | // have we NOT already logged that we are using an insane number of threads in the past |
| | | 726 | | int now = Environment.TickCount; |
| | | 727 | | int lastWarning = _highThreadsWarningTickCount; |
| | | 728 | | if ((_testMode && lastWarning == 0) || TimeElapsed(lastWarning, now) > HighThreadCountWa |
| | | 729 | | { |
| | | 730 | | // race to log a warning--did we win the race? |
| | | 731 | | if (Interlocked.CompareExchange(ref _highThreadsWarningTickCount, now, lastWarning) |
| | | 732 | | { |
| | | 733 | | Logger.Filter("Busy", AmbientLogLevel.Warning)?.Log(new { Action = "WorkerBusy", |
| | | 734 | | } |
| | | 735 | | } |
| | | 736 | | // now we will just carry on because we will not expand beyond the number of threads we |
| | | 737 | | } |
| | | 738 | | // CPU low enough to create new workers? (if the CPU is high, more workers would just gum u |
| | | 739 | | else if (recentCpuUsage < MinAddThreadsCpuUsage) |
| | | 740 | | { |
| | | 741 | | // initialize enough workers to maintain the buffer thread count |
| | | 742 | | for (int i = 0; i < _bufferWorkerThreads - readyWorkers; ++i) |
| | | 743 | | { |
| | | 744 | | // create a new worker |
| | | 745 | | FifoWorker worker = CreateWorker(); |
| | | 746 | | Debug.Assert(!worker.IsBusy); |
| | | 747 | | _readyWorkerList.Push(worker); |
| | | 748 | | } |
| | | 749 | | FifoTaskScheduler.Logger.Filter("Scale", AmbientLogLevel.Debug)?.Log(new { Action = "Sca |
| | | 750 | | // record the expansion time so we don't retire anything for at least a minute |
| | | 751 | | lastCreationTicks = Environment.TickCount; |
| | | 752 | | // record that we just finished a scale up |
| | | 753 | | Interlocked.Exchange(ref _lastScaleUpTime, AmbientClock.UtcNow.Ticks); |
| | | 754 | | } |
| | | 755 | | // else we *might* be able to use more workers, but the CPU is pretty high, so let's not |
| | | 756 | | } |
| | | 757 | | // enough ready workers that we could get by with less? |
| | | 758 | | else if (readyWorkers > Math.Max(2, _bufferWorkerThreads)) |
| | | 759 | | { |
| | | 760 | | // haven't had an inline execution or new worker creation or removed any workers for a while |
| | | 761 | | if (_testMode || ( |
| | | 762 | | ticksSinceCreation > RetireCheckAfterCreationTickCount && |
| | | 763 | | ticksSinceInlineExecution > RetireCheckAfterCreationTickCount && |
| | | 764 | | ticksSinceRetirement > RetireCheckFastestRetirementFrequencyTickCount |
| | | 765 | | )) |
| | | 766 | | { |
| | | 767 | | // was the highest concurrency since the last time we checked such that we didn't need m |
| | | 768 | | if (_peakConcurrentUsageSinceLastRetirementCheck < Math.Max(1, totalWorkers - _bufferWor |
| | | 769 | | { |
| | | 770 | | // retire one worker |
| | | 771 | | RetireOneWorker(); |
| | | 772 | | FifoTaskScheduler.Logger.Filter("Scale", AmbientLogLevel.Debug)?.Log(new { Action = |
| | | 773 | | // record that we retired threads just now |
| | | 774 | | lastRetirementTicks = Environment.TickCount; |
| | | 775 | | } |
| | | 776 | | // reset the concurrency |
| | | 777 | | Interlocked.Exchange(ref _peakConcurrentUsageSinceLastRetirementCheck, 0); |
| | | 778 | | // record that we just finished a scale down |
| | | 779 | | Interlocked.Exchange(ref _lastScaleDownTime, AmbientClock.UtcNow.Ticks); |
| | | 780 | | } |
| | | 781 | | } |
| | | 782 | | }); |
| | | 783 | | } |
| | | 784 | | }); |
| | | 785 | | } |
| | | 786 | | internal void ExecuteWithCatchAndLog(Action action) |
| | | 787 | | { |
| | | 788 | | try |
| | | 789 | | { |
| | | 790 | | action(); |
| | | 791 | | } |
| | | 792 | | catch (Exception ex) |
| | | 793 | | { |
| | | 794 | | if (ex is ThreadAbortException || ex is TaskCanceledException) Logger.Filter("AsyncException", AmbientLo |
| | | 795 | | else Logger.Filter("AsyncException", AmbientLogLevel.Error)?.Log(new { Action = "CriticalException", Sch |
| | | 796 | | } |
| | | 797 | | } |
| | | 798 | | |
| | | 799 | | private bool RetireOneWorker() |
| | | 800 | | { |
| | | 801 | | FifoWorker? workerToStop = _readyWorkerList.Pop(); |
| | | 802 | | // none left? |
| | | 803 | | if (workerToStop is null) |
| | | 804 | | { |
| | | 805 | | return false; |
| | | 806 | | } |
| | | 807 | | else Debug.Assert(!workerToStop.IsBusy); |
| | | 808 | | |
| | | 809 | | Interlocked.Decrement(ref _workers); |
| | | 810 | | workerToStop.Stop(); |
| | | 811 | | return true; |
| | | 812 | | } |
| | | 813 | | |
| | | 814 | | internal void OnWorkerReady(FifoWorker worker) |
| | | 815 | | { |
| | | 816 | | // add the worker back to the ready worker list |
| | | 817 | | Debug.Assert(!worker.IsBusy); |
| | | 818 | | _readyWorkerList.Push(worker); |
| | | 819 | | } |
| | | 820 | | private void ReportQueueMiss() |
| | | 821 | | { |
| | | 822 | | if (!Stopping) |
| | | 823 | | { |
| | | 824 | | // record this miss |
| | | 825 | | Interlocked.Exchange(ref _lastInlineExecutionTicks, Environment.TickCount); |
| | | 826 | | SchedulerInlineExecutions?.IncrementRaw(); |
| | | 827 | | // notify any subscribers of the miss |
| | | 828 | | TaskInlined?.Invoke(this, new TaskInlinedEventArgs()); |
| | | 829 | | // wake the master thread so it will add more threads ASAP |
| | | 830 | | _wakeSchedulerMasterThread.Set(); |
| | | 831 | | Logger.Filter("Busy", AmbientLogLevel.Warning)?.Log(new { Action = "NoAvailableWorkers", SchedulerName = |
| | | 832 | | } |
| | | 833 | | } |
| | | 834 | | |
| | | 835 | | /// <summary> |
| | | 836 | | /// Transfers asynchronous work to this scheduler, running continuations within the scheduler so that subsequent |
| | | 837 | | /// </summary> |
| | | 838 | | /// <typeparam name="T">The type returned by the function.</typeparam> |
| | | 839 | | /// <param name="func">The asynchronous function that does the work.</param> |
| | | 840 | | public Task<T> TransferWork<T>(Func<ValueTask<T>> func) |
| | | 841 | | { |
| | | 842 | | #if NET6_0_OR_GREATER |
| | | 843 | | ArgumentNullException.ThrowIfNull(func); |
| | | 844 | | #else |
| | | 845 | | if (func == null) throw new ArgumentNullException(nameof(func)); |
| | | 846 | | #endif |
| | | 847 | | return Task.Factory.StartNew(() => ExecuteTask(async () => |
| | | 848 | | { |
| | | 849 | | return await func(); |
| | | 850 | | }).AsTask(), CancellationToken.None, TaskCreationOptions.None, this).Unwrap(); |
| | | 851 | | } |
| | | 852 | | /// <summary> |
| | | 853 | | /// Transfers asynchronous work to this scheduler, running continuations within the scheduler so that subsequent |
| | | 854 | | /// Exceptions are thrown from the function out to the caller. |
| | | 855 | | /// </summary> |
| | | 856 | | /// <param name="func">The asynchronous function that does the work.</param> |
| | | 857 | | public Task TransferWork(Func<ValueTask> func) |
| | | 858 | | { |
| | | 859 | | #if NET6_0_OR_GREATER |
| | | 860 | | ArgumentNullException.ThrowIfNull(func); |
| | | 861 | | #else |
| | | 862 | | if (func == null) throw new ArgumentNullException(nameof(func)); |
| | | 863 | | #endif |
| | | 864 | | return Task.Factory.StartNew(() => ExecuteTask(async () => |
| | | 865 | | { |
| | | 866 | | await func(); |
| | | 867 | | }).AsTask(), CancellationToken.None, TaskCreationOptions.None, this).Unwrap(); |
| | | 868 | | } |
| | | 869 | | /// <summary> |
| | | 870 | | /// Runs a long-running function, running it entirely on a scheduler thread. |
| | | 871 | | /// </summary> |
| | | 872 | | /// <param name="func">The func to run on a scheduler thread. The function may be async but should not be "asyn |
| | | 873 | | /// <returns>A <see cref="Task"/> which may be used to wait for the action to complete. Presumably you want the |
| | | 874 | | /// <remarks>Exceptions thrown from the function will be available to be observed through the returned <see cref |
| | | 875 | | public Task<T> Run<T>(Func<T> func) |
| | | 876 | | { |
| | | 877 | | #if NET6_0_OR_GREATER |
| | | 878 | | ArgumentNullException.ThrowIfNull(func); |
| | | 879 | | #else |
| | | 880 | | if (func == null) throw new ArgumentNullException(nameof(func)); |
| | | 881 | | #endif |
| | | 882 | | #if NET7_0_OR_GREATER |
| | | 883 | | ObjectDisposedException.ThrowIf(Stopping, this); |
| | | 884 | | #else |
| | | 885 | | if (Stopping) throw new ObjectDisposedException(nameof(FifoTaskScheduler)); |
| | | 886 | | #endif |
| | | 887 | | TaskCompletionSource<T> tcs = new(); |
| | | 888 | | SchedulerInvocations?.IncrementRaw(); |
| | | 889 | | // try to get a ready thread |
| | | 890 | | FifoWorker? worker = _readyWorkerList.Pop(); |
| | | 891 | | // no ready workers? |
| | | 892 | | if (worker is null) |
| | | 893 | | { |
| | | 894 | | // create a new worker right now, but don't put it on the ready list because we're going to use it immed |
| | | 895 | | #pragma warning disable CA2000 // Dispose objects before losing scope (this gets put into a collection and disposed of l |
| | | 896 | | worker = CreateWorker(); |
| | | 897 | | #pragma warning restore CA2000 // Dispose objects before losing scope |
| | | 898 | | Debug.Assert(!worker.IsBusy); |
| | | 899 | | // wake the master thread so it will add more threads ASAP so we don't have to do this here |
| | | 900 | | _wakeSchedulerMasterThread.Set(); |
| | | 901 | | } |
| | | 902 | | else |
| | | 903 | | { |
| | | 904 | | Debug.Assert(!worker.IsBusy); |
| | | 905 | | } |
| | | 906 | | |
| | | 907 | | worker.Invoke(() => |
| | | 908 | | { |
| | | 909 | | _ = Task.Factory.StartNew(() => |
| | | 910 | | { |
| | | 911 | | try |
| | | 912 | | { |
| | | 913 | | // run SetResult inside ExecuteAction so that continuations also run with this task scheduler |
| | | 914 | | tcs.SetResult(func()); |
| | | 915 | | } |
| | | 916 | | catch (Exception e) |
| | | 917 | | { |
| | | 918 | | // run SetException inside ExecuteAction so that continuations also run with this task scheduler |
| | | 919 | | tcs.SetException(e); |
| | | 920 | | } |
| | | 921 | | }, CancellationToken.None, TaskCreationOptions.None, this); |
| | | 922 | | }); |
| | | 923 | | return tcs.Task; |
| | | 924 | | } |
| | | 925 | | /// <summary> |
| | | 926 | | /// Runs a long-running action, running it entirely on a scheduler thread, but gets a <see cref="Task"/> we can |
| | | 927 | | /// </summary> |
| | | 928 | | /// <param name="action">The action to run on a scheduler thread. May be an "async void" action.</param> |
| | | 929 | | /// <returns>A <see cref="Task"/> which may be used to wait for the function to complete after it is cancelled ( |
| | | 930 | | /// <remarks>Exceptions thrown from the function will be available to be observed through the returned <see cref |
| | | 931 | | public Task Run(Action action) |
| | | 932 | | { |
| | | 933 | | #if NET6_0_OR_GREATER |
| | | 934 | | ArgumentNullException.ThrowIfNull(action); |
| | | 935 | | #else |
| | | 936 | | if (action == null) throw new ArgumentNullException(nameof(action)); |
| | | 937 | | #endif |
| | | 938 | | #if NET7_0_OR_GREATER |
| | | 939 | | ObjectDisposedException.ThrowIf(Stopping, this); |
| | | 940 | | #else |
| | | 941 | | if (Stopping) throw new ObjectDisposedException(nameof(FifoTaskScheduler)); |
| | | 942 | | #endif |
| | | 943 | | TaskCompletionSource<bool> tcs = new(); |
| | | 944 | | SchedulerInvocations?.IncrementRaw(); |
| | | 945 | | // try to get a ready thread |
| | | 946 | | FifoWorker? worker = _readyWorkerList.Pop(); |
| | | 947 | | // no ready workers? |
| | | 948 | | if (worker is null) |
| | | 949 | | { |
| | | 950 | | // create a new worker right now, but don't put it on the ready list because we're going to use it immed |
| | | 951 | | #pragma warning disable CA2000 // Dispose objects before losing scope (this gets put into a collection and disposed of l |
| | | 952 | | worker = CreateWorker(); |
| | | 953 | | #pragma warning restore CA2000 // Dispose objects before losing scope |
| | | 954 | | Debug.Assert(!worker.IsBusy); |
| | | 955 | | // wake the master thread so it will add more threads ASAP so we don't have to do this here |
| | | 956 | | _wakeSchedulerMasterThread.Set(); |
| | | 957 | | } |
| | | 958 | | else |
| | | 959 | | { |
| | | 960 | | Debug.Assert(!worker.IsBusy); |
| | | 961 | | } |
| | | 962 | | worker.Invoke(() => |
| | | 963 | | { |
| | | 964 | | _ = Task.Factory.StartNew(() => |
| | | 965 | | { |
| | | 966 | | try |
| | | 967 | | { |
| | | 968 | | action(); |
| | | 969 | | // run SetResult inside ExecuteAction so that any continuations also run with this task schedule |
| | | 970 | | tcs.SetResult(true); |
| | | 971 | | } |
| | | 972 | | catch (Exception e) |
| | | 973 | | { |
| | | 974 | | // run SetException inside ExecuteAction so that continuations also run with this task scheduler |
| | | 975 | | tcs.SetException(e); |
| | | 976 | | } |
| | | 977 | | }, CancellationToken.None, TaskCreationOptions.None, this); |
| | | 978 | | }); |
| | | 979 | | return tcs.Task; |
| | | 980 | | } |
| | | 981 | | /// <summary> |
| | | 982 | | /// Runs a fire-and-forget action, running it entirely on a scheduler thread. |
| | | 983 | | /// </summary> |
| | | 984 | | /// <param name="action">The action to run asynchronously. May be an "async void" action.</param> |
| | | 985 | | /// <remarks>Note that exceptions throw from <paramref name="action"/> will be unobserved.</remarks> |
| | | 986 | | [SuppressMessage("Design", "CA1030:Use events where appropriate", Justification = "This should be obvious. The |
| | | 987 | | public void FireAndForget(Action action) |
| | | 988 | | { |
| | | 989 | | #if NET6_0_OR_GREATER |
| | | 990 | | ArgumentNullException.ThrowIfNull(action); |
| | | 991 | | #else |
| | | 992 | | if (action == null) throw new ArgumentNullException(nameof(action)); |
| | | 993 | | #endif |
| | | 994 | | #if NET7_0_OR_GREATER |
| | | 995 | | ObjectDisposedException.ThrowIf(Stopping, this); |
| | | 996 | | #else |
| | | 997 | | if (Stopping) throw new ObjectDisposedException(nameof(FifoTaskScheduler)); |
| | | 998 | | #endif |
| | | 999 | | SchedulerInvocations?.IncrementRaw(); |
| | | 1000 | | // try to get a ready thread |
| | | 1001 | | FifoWorker? worker = _readyWorkerList.Pop(); |
| | | 1002 | | // no ready workers? |
| | | 1003 | | if (worker is null) |
| | | 1004 | | { |
| | | 1005 | | // create a new worker right now, but don't put it on the ready list because we're going to use it immed |
| | | 1006 | | #pragma warning disable CA2000 // Dispose objects before losing scope (this gets put into a collection and disposed of l |
| | | 1007 | | worker = CreateWorker(); |
| | | 1008 | | #pragma warning restore CA2000 // Dispose objects before losing scope |
| | | 1009 | | Debug.Assert(!worker.IsBusy); |
| | | 1010 | | // wake the master thread so it will add more threads ASAP so we don't have to do this here |
| | | 1011 | | _wakeSchedulerMasterThread.Set(); |
| | | 1012 | | } |
| | | 1013 | | else |
| | | 1014 | | { |
| | | 1015 | | Debug.Assert(!worker.IsBusy); |
| | | 1016 | | } |
| | | 1017 | | worker.Invoke(() => |
| | | 1018 | | { |
| | | 1019 | | _ = Task.Factory.StartNew(action, CancellationToken.None, TaskCreationOptions.None, this); |
| | | 1020 | | }); |
| | | 1021 | | } |
| | | 1022 | | /// <summary> |
| | | 1023 | | /// Runs the specified action in the context of the high performance FIFO task scheduler. |
| | | 1024 | | /// Everything up to the first await will run inline, but continuations will run in the context of the high perf |
| | | 1025 | | /// </summary> |
| | | 1026 | | /// <param name="action">The <see cref="Action"/> to run.</param> |
| | | 1027 | | internal void ExecuteAction(Action action) |
| | | 1028 | | { |
| | | 1029 | | // we now have a worker that is busy |
| | | 1030 | | Interlocked.Increment(ref _busyWorkers); |
| | | 1031 | | // keep track of the maximum concurrent usage |
| | | 1032 | | InterlockedUtilities.TryOptomisticMax(ref _peakConcurrentUsageSinceLastRetirementCheck, _busyWorkers); |
| | | 1033 | | try |
| | | 1034 | | { |
| | | 1035 | | action(); |
| | | 1036 | | } |
| | | 1037 | | catch (Exception ex) |
| | | 1038 | | { |
| | | 1039 | | RaiseUnhandledException(ex); |
| | | 1040 | | } |
| | | 1041 | | finally |
| | | 1042 | | { |
| | | 1043 | | // the worker is no longer busy |
| | | 1044 | | Interlocked.Decrement(ref _busyWorkers); |
| | | 1045 | | } |
| | | 1046 | | } |
| | | 1047 | | /// <summary> |
| | | 1048 | | /// Executes an asynchronous function with the high performance FIFO task scheduler as the default synchronizati |
| | | 1049 | | /// This function must not be awaited because awaits outside of this context may cause continuations to run outs |
| | | 1050 | | /// </summary> |
| | | 1051 | | /// <typeparam name="T">The type that will be returned from the async function.</typeparam> |
| | | 1052 | | /// <param name="func">The async function to invoke within the context of the high performance FIFO task schedul |
| | | 1053 | | private async ValueTask<T> ExecuteTask<T>(Func<ValueTask<T>> func) |
| | | 1054 | | { |
| | | 1055 | | // we now have a worker that is busy |
| | | 1056 | | Interlocked.Increment(ref _busyWorkers); |
| | | 1057 | | // keep track of the maximum concurrent usage |
| | | 1058 | | InterlockedUtilities.TryOptomisticMax(ref _peakConcurrentUsageSinceLastRetirementCheck, _busyWorkers); |
| | | 1059 | | try |
| | | 1060 | | { |
| | | 1061 | | return await func(); // the whole point of this function is to execute the task in the high performance |
| | | 1062 | | } |
| | | 1063 | | finally |
| | | 1064 | | { |
| | | 1065 | | // the worker is no longer busy |
| | | 1066 | | Interlocked.Decrement(ref _busyWorkers); |
| | | 1067 | | } |
| | | 1068 | | } |
| | | 1069 | | /// <summary> |
| | | 1070 | | /// Executes an asynchronous function with the high performance FIFO task scheduler as the default synchronizati |
| | | 1071 | | /// This function must not be awaited because awaits outside of this context may cause continuations to run outs |
| | | 1072 | | /// </summary> |
| | | 1073 | | /// <param name="func">The async function to invoke within the context of the high performance FIFO task schedul |
| | | 1074 | | private async ValueTask ExecuteTask(Func<ValueTask> func) |
| | | 1075 | | { |
| | | 1076 | | // we now have a worker that is busy |
| | | 1077 | | Interlocked.Increment(ref _busyWorkers); |
| | | 1078 | | // keep track of the maximum concurrent usage |
| | | 1079 | | InterlockedUtilities.TryOptomisticMax(ref _peakConcurrentUsageSinceLastRetirementCheck, _busyWorkers); |
| | | 1080 | | try |
| | | 1081 | | { |
| | | 1082 | | await func(); // the whole point of this function is to execute the task in the high performance synchro |
| | | 1083 | | } |
| | | 1084 | | finally |
| | | 1085 | | { |
| | | 1086 | | // the worker is no longer busy |
| | | 1087 | | Interlocked.Decrement(ref _busyWorkers); |
| | | 1088 | | } |
| | | 1089 | | } |
| | | 1090 | | internal IEnumerable<Task> GetScheduledTasksDirect() |
| | | 1091 | | { |
| | | 1092 | | return GetScheduledTasks(); |
| | | 1093 | | } |
| | | 1094 | | /// <summary> |
| | | 1095 | | /// Gets the list of scheduled tasks. In this case, this is always empty, as all tasks are either executed imme |
| | | 1096 | | /// </summary> |
| | | 1097 | | /// <returns>An empty enumeration.</returns> |
| | | 1098 | | protected override IEnumerable<Task> GetScheduledTasks() |
| | | 1099 | | { |
| | | 1100 | | return Array.Empty<Task>(); |
| | | 1101 | | } |
| | | 1102 | | internal void QueueTaskDirect(Task task) |
| | | 1103 | | { |
| | | 1104 | | QueueTask(task); |
| | | 1105 | | } |
| | | 1106 | | /// <summary> |
| | | 1107 | | /// Queues the specified task to the high performance FIFO scheduler, or runs it immediately if there are no wor |
| | | 1108 | | /// Any exceptions will go to the unhandled exception handler. |
| | | 1109 | | /// </summary> |
| | | 1110 | | /// <param name="task">The <see cref="Task"/> which is to be executed.</param> |
| | | 1111 | | protected override void QueueTask(Task task) |
| | | 1112 | | { |
| | | 1113 | | #if NET6_0_OR_GREATER |
| | | 1114 | | ArgumentNullException.ThrowIfNull(task); |
| | | 1115 | | #else |
| | | 1116 | | if (task == null) throw new ArgumentNullException(nameof(task)); |
| | | 1117 | | #endif |
| | | 1118 | | #if NET7_0_OR_GREATER |
| | | 1119 | | ObjectDisposedException.ThrowIf(_stopMasterThread != 0, this); |
| | | 1120 | | #else |
| | | 1121 | | if (_stopMasterThread != 0) throw new ObjectDisposedException(nameof(FifoTaskScheduler)); |
| | | 1122 | | #endif |
| | | 1123 | | SchedulerInvocations?.IncrementRaw(); |
| | | 1124 | | // try to get a ready thread |
| | | 1125 | | FifoWorker? worker = _readyWorkerList.Pop(); |
| | | 1126 | | // no ready workers? |
| | | 1127 | | if (worker is null || Stopping) |
| | | 1128 | | { |
| | | 1129 | | ReportQueueMiss(); |
| | | 1130 | | // if the CPU is above the max, let's slow things down here by just sleeping for a bit |
| | | 1131 | | if (CpuMonitor.RecentUsage > MaxCpuUsage) Thread.Sleep(10); |
| | | 1132 | | // execute the action inline |
| | | 1133 | | TryExecuteTaskInline(task, false); |
| | | 1134 | | return; |
| | | 1135 | | } |
| | | 1136 | | else |
| | | 1137 | | { |
| | | 1138 | | Debug.Assert(!worker.IsBusy); |
| | | 1139 | | } |
| | | 1140 | | worker.Invoke(() => |
| | | 1141 | | { |
| | | 1142 | | TryExecuteTask(task); // calling this system function takes care of unobserved task exc |
| | | 1143 | | }); |
| | | 1144 | | } |
| | | 1145 | | /// <summary> |
| | | 1146 | | /// Attempts to execute the specified task inline. |
| | | 1147 | | /// </summary> |
| | | 1148 | | /// <param name="task">The <see cref="Task"/> to be executed.</param> |
| | | 1149 | | /// <param name="taskWasPreviouslyQueued">Whether or not the task was previously queued.</param> |
| | | 1150 | | /// <returns>Whether or not the task ran inline.</returns> |
| | | 1151 | | protected override bool TryExecuteTaskInline(Task task, bool taskWasPreviouslyQueued) |
| | | 1152 | | { |
| | | 1153 | | return !taskWasPreviouslyQueued && TryExecuteTask(task); |
| | | 1154 | | } |
| | | 1155 | | /// <summary> |
| | | 1156 | | /// Gets the maximum number of tasks that can be concurrently running under this scheduler. |
| | | 1157 | | /// </summary> |
| | | 1158 | | public override int MaximumConcurrencyLevel => _maxWorkerThreads; |
| | | 1159 | | } |
| | | 1160 | | |
| | | 1161 | | internal class IntrusiveSinglyLinkedListNode |
| | | 1162 | | { |
| | | 1163 | | internal IntrusiveSinglyLinkedListNode? fNextNode; |
| | | 1164 | | } |
| | | 1165 | | |
| | | 1166 | | /// <summary> |
| | | 1167 | | /// A thread-safe intrusive stack. All methods are thread-safe. |
| | | 1168 | | /// </summary> |
| | | 1169 | | /// <typeparam name="TYPE">The type of item to store in the stack. Must inherit from <see cref="IntrusiveSinglyLink |
| | | 1170 | | internal class InterlockedSinglyLinkedList<TYPE> where TYPE : IntrusiveSinglyLinkedListNode |
| | | 1171 | | { |
| | | 1172 | | private int fCount; |
| | | 1173 | | private int fPopping; |
| | | 1174 | | private readonly IntrusiveSinglyLinkedListNode fRoot; // we use a circular list instead of null because it allow |
| | | 1175 | | |
| | | 1176 | | /// <summary> |
| | | 1177 | | /// Constructs the list. |
| | | 1178 | | /// </summary> |
| | | 1179 | | public InterlockedSinglyLinkedList() |
| | | 1180 | | { |
| | | 1181 | | fRoot = new IntrusiveSinglyLinkedListNode(); |
| | | 1182 | | fRoot.fNextNode = fRoot; |
| | | 1183 | | Validate(); |
| | | 1184 | | } |
| | | 1185 | | |
| | | 1186 | | /// <summary> |
| | | 1187 | | /// Pushes the specified node onto the top of the stack. |
| | | 1188 | | /// </summary> |
| | | 1189 | | /// <param name="node">The node to push onto the top of the stack.</param> |
| | | 1190 | | /// <remarks>The specified node must NOT already be in another stack and must not be simultaneously added or rem |
| | | 1191 | | public void Push(TYPE node) |
| | | 1192 | | { |
| | | 1193 | | #if NET6_0_OR_GREATER |
| | | 1194 | | ArgumentNullException.ThrowIfNull(node); |
| | | 1195 | | #else |
| | | 1196 | | if (node == null) throw new ArgumentNullException(nameof(node)); |
| | | 1197 | | #endif |
| | | 1198 | | Validate(); |
| | | 1199 | | // already in another list? |
| | | 1200 | | if (node.fNextNode != null) |
| | | 1201 | | { |
| | | 1202 | | Validate(); |
| | | 1203 | | throw new InvalidOperationException("The specified node is already in a list!"); |
| | | 1204 | | } |
| | | 1205 | | // get the current top, which will be the old one if we succeed |
| | | 1206 | | IntrusiveSinglyLinkedListNode? oldTop = fRoot.fNextNode; |
| | | 1207 | | // loop until we win the race to insert us at the top |
| | | 1208 | | do |
| | | 1209 | | { |
| | | 1210 | | // set this node's next node as the node we just got (we'll change it if we don't win the race) |
| | | 1211 | | node.fNextNode = oldTop; |
| | | 1212 | | // race to place this node in as the top node--did we win? |
| | | 1213 | | if (Interlocked.CompareExchange(ref fRoot.fNextNode, node, oldTop) == oldTop) |
| | | 1214 | | { |
| | | 1215 | | // increment the node count (it will be one off temporarily, but since the list can change at any ti |
| | | 1216 | | Interlocked.Increment(ref fCount); |
| | | 1217 | | Validate(); |
| | | 1218 | | return; |
| | | 1219 | | } |
| | | 1220 | | // else do it all again, get the current top, which will be the old one if we succeed |
| | | 1221 | | oldTop = fRoot.fNextNode; |
| | | 1222 | | } while (true); |
| | | 1223 | | } |
| | | 1224 | | |
| | | 1225 | | /// <summary> |
| | | 1226 | | /// Pops off the top node on the stack and returns it. |
| | | 1227 | | /// </summary> |
| | | 1228 | | /// <returns>The top node, or <b>null</b> if there are no items in the stack.</returns> |
| | | 1229 | | public TYPE? Pop() |
| | | 1230 | | { |
| | | 1231 | | Validate(); |
| | | 1232 | | IntrusiveSinglyLinkedListNode? ret; |
| | | 1233 | | // wait until no other threads are popping |
| | | 1234 | | while (Interlocked.CompareExchange(ref fPopping, 1, 0) != 0) { } |
| | | 1235 | | try |
| | | 1236 | | { |
| | | 1237 | | // loop while there something in the list to remove |
| | | 1238 | | while ((ret = fRoot.fNextNode) != fRoot) |
| | | 1239 | | { |
| | | 1240 | | // get the new top |
| | | 1241 | | IntrusiveSinglyLinkedListNode? newTop = ret?.fNextNode; |
| | | 1242 | | // another thread better not have already popped this node, but just in case, check here |
| | | 1243 | | if (newTop != null) |
| | | 1244 | | { |
| | | 1245 | | // try to exchange the new top into the top position--did we win the race against a pusher? |
| | | 1246 | | if (Interlocked.CompareExchange(ref fRoot.fNextNode, newTop, ret) == ret) |
| | | 1247 | | { |
| | | 1248 | | // decrement the node count (it will be one off temporarily, but since the list can change a |
| | | 1249 | | Interlocked.Decrement(ref fCount); |
| | | 1250 | | // clear the next pointer because we are no longer in the list |
| | | 1251 | | ret!.fNextNode = null; // this is a little complicated, but if you look closely, ret ca |
| | | 1252 | | Validate(); |
| | | 1253 | | // return the node that was removed |
| | | 1254 | | return (TYPE)ret; |
| | | 1255 | | } |
| | | 1256 | | // try again from the beginning |
| | | 1257 | | } |
| | | 1258 | | else Debug.Fail("newTop was null!"); |
| | | 1259 | | } |
| | | 1260 | | } |
| | | 1261 | | finally |
| | | 1262 | | { |
| | | 1263 | | // we are no longer popping |
| | | 1264 | | Interlocked.Exchange(ref fPopping, 0); |
| | | 1265 | | } |
| | | 1266 | | Validate(); |
| | | 1267 | | // nothing there to pop! |
| | | 1268 | | return null; |
| | | 1269 | | } |
| | | 1270 | | |
| | | 1271 | | [Conditional("DEBUG")] |
| | | 1272 | | internal void Validate() |
| | | 1273 | | { |
| | | 1274 | | // we better still have a valid root! |
| | | 1275 | | Debug.Assert(fRoot is not null && fRoot is not TYPE); |
| | | 1276 | | // root node better not have a null next pointer |
| | | 1277 | | Debug.Assert(fRoot?.fNextNode != null); |
| | | 1278 | | } |
| | | 1279 | | |
| | | 1280 | | /// <summary> |
| | | 1281 | | /// Clear all items from the list. May remove nodes that are added after this function starts, and items may be |
| | | 1282 | | /// </summary> |
| | | 1283 | | public void Clear() |
| | | 1284 | | { |
| | | 1285 | | Validate(); |
| | | 1286 | | // pop from the top until the list is empty |
| | | 1287 | | while (Pop() != null) |
| | | 1288 | | { |
| | | 1289 | | // do nothing |
| | | 1290 | | } |
| | | 1291 | | Validate(); |
| | | 1292 | | } |
| | | 1293 | | |
| | | 1294 | | /// <summary> |
| | | 1295 | | /// Gets the number of items in the list, which could change before if could be useful. |
| | | 1296 | | /// </summary> |
| | | 1297 | | public int Count |
| | | 1298 | | { |
| | | 1299 | | get |
| | | 1300 | | { |
| | | 1301 | | Validate(); |
| | | 1302 | | return fCount; |
| | | 1303 | | } |
| | | 1304 | | } |
| | | 1305 | | } |
| | | 1306 | | } |