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Added unit tests for parallel background worker; fixed some issues with the parallel background worker; added failing unit test for almost equal checks with doubles; fixed a typo

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git-svn-id: file:///srv/devel/repo-conversion/nusu@291 d2e56fa2-650e-0410-a79f-9358c0239efd
This commit is contained in:
Markus Ewald 2014-02-20 14:33:40 +00:00
parent a18cb63fc5
commit feac2b9c89
5 changed files with 334 additions and 41 deletions
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1
Nuclex.Support (net-4.0).csproj
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@ -215,6 +215,7 @@
<DependentUpon>LicenseKey.cs</DependentUpon>
</Compile>
<Compile Include="Source\ParallelBackgroundWorker.cs" />
<Compile Include="Source\ParallelBackgroundWorker.Test.cs" />
<Compile Include="Source\Parsing\CommandLine.Argument.cs">
<DependentUpon>CommandLine.cs</DependentUpon>
</Compile>

27
Source/FloatHelper.Test.cs
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@ -148,7 +148,12 @@ namespace Nuclex.Support {
// If both are negative -> fine
// If both are positive -> fine
// If different -> Measure both distances to zero in ulps and sum them
public void NegativeZeroEqualsPositiveZero() {
/// <summary>
/// Verifies that the negative floating point zero is within one ulp of the positive
/// floating point zero and vice versa
/// </summary>
[Test]
public void NegativeZeroFloatEqualsPositiveZero() {
float zero = 0.0f;
float zeroPlusOneUlp = FloatHelper.ReinterpretAsFloat(
FloatHelper.ReinterpretAsInt(zero) + 1
@ -163,6 +168,26 @@ namespace Nuclex.Support {
Assert.IsTrue(FloatHelper.AreAlmostEqual(zero, zeroMinusOneUlp, 1));
}
/// <summary>
/// Verifies that the negative double precision floating point zero is within one ulp
/// of the positive double precision floating point zero and vice versa
/// </summary>
[Test]
public void NegativeZeroDoubleEqualsPositiveZero() {
double zero = 0.0;
double zeroPlusOneUlp = FloatHelper.ReinterpretAsDouble(
FloatHelper.ReinterpretAsLong(zero) + 1
);
double zeroMinusOneUlp = -zeroPlusOneUlp;
bool test = FloatHelper.AreAlmostEqual(zeroMinusOneUlp, zeroPlusOneUlp, 1);
Assert.IsFalse(FloatHelper.AreAlmostEqual(zero, zeroPlusOneUlp, 0));
Assert.IsTrue(FloatHelper.AreAlmostEqual(zero, zeroPlusOneUlp, 1));
Assert.IsFalse(FloatHelper.AreAlmostEqual(zero, zeroMinusOneUlp, 0));
Assert.IsTrue(FloatHelper.AreAlmostEqual(zero, zeroMinusOneUlp, 1));
}
}
} // namespace Nuclex.Support

2
Source/IntegerHelper.cs
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@ -77,7 +77,7 @@ namespace Nuclex.Support {
return value;
}
/// <summary>Returns the number of bits set in an </summary>
/// <summary>Returns the number of bits set in an integer</summary>
/// <param name="value">Value whose bits will be counted</param>
/// <returns>The number of bits set in the integer</returns>
public static int CountBits(this int value) {

239
Source/ParallelBackgroundWorker.Test.cs Normal file
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@ -0,0 +1,239 @@
#region CPL License
/*
Nuclex Framework
Copyright (C) 2002-2013 Nuclex Development Labs
This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.
You should have received a copy of the IBM Common Public
License along with this library
*/
#endregion
using System;
using System.IO;
#if UNITTEST
using NUnit.Framework;
using System.Threading;
using System.Collections.Generic;
namespace Nuclex.Support {
/// <summary>Unit Test for the parallel background worker class</summary>
[TestFixture]
public class ParallelBackgroundWorkerTest {
private class TestWorker : ParallelBackgroundWorker<object> {
/// <summary>Initializes a new parallel background worker with unlimited threads</summary>
public TestWorker() : base() { }
/// <summary>
/// Initializes a new parallel background worker running the specified number
/// of tasks in parallel
/// </summary>
/// <param name="threadCount">
/// Number of tasks to run in parallel (if positive) or number of CPU cores to leave
/// unused (if negative).
/// </param>
/// <remarks>
/// If a negative number of threads is used, at least one thread will be always
/// be created, so specifying -2 on a single-core system will still occupy
/// the only core.
/// </remarks>
public TestWorker(int threadCount) : base(threadCount) {}
/// <summary>
/// Initializes a new parallel background worker that uses the specified name for
/// its worker threads.
/// </summary>
/// <param name="name">Name that will be assigned to the worker threads</param>
public TestWorker(string name) : base(name) {}
/// <summary>
/// Initializes a new parallel background worker that uses the specified name for
/// its worker threads and running the specified number of tasks in parallel.
/// </summary>
/// <param name="name">Name that will be assigned to the worker threads</param>
/// <param name="threadCount">
/// Number of tasks to run in parallel (if positive) or number of CPU cores to leave
/// unused (if negative).
/// </param>
/// <remarks>
/// If a negative number of threads is used, at least one thread will be always
/// be created, so specifying -2 on a single-core system will still occupy
/// the only core.
/// </remarks>
public TestWorker(string name, int threadCount) : base(name, threadCount) { }
/// <summary>Called in a thread to execute a single task</summary>
/// <param name="task">Task that should be executed</param>
/// <param name="cancellationToken">
/// Cancellation token through which the method can be signalled to cancel
/// </param>
protected override void Run(object task, CancellationToken cancellationToken) {
if(this.ThrowException) {
throw new Exception("Something went wrong");
}
if(this.WaitEvent != null) {
this.WaitEvent.WaitOne();
}
this.WasCancelled = cancellationToken.IsCancellationRequested;
if(this.Tasks != null) {
this.Tasks.Add(task);
}
}
public bool ThrowException;
public ManualResetEvent WaitEvent;
public bool WasCancelled;
public ICollection<object> Tasks;
}
/// <summary>Verifies that the background worker has a default constructor</summary>
[Test]
public void CanBeDefaultConstructed() {
using(new TestWorker()) { }
}
/// <summary>
/// Verifies that a background worker can be constructed that uses a fixed number
/// of threads
/// </summary>
[Test]
public void CanUseFixedNumberOfThreads() {
using(new TestWorker(4)) { }
}
/// <summary>
/// Verifies that a background worker can be constructed that leaves free a fixed
/// number of CPU cores
/// </summary>
[Test]
public void CanPreserveFixedNumberOfCores() {
using(new TestWorker(-2)) { }
}
/// <summary>
/// Verifies that a background worker can be constructed using a specific name
/// for its worker threads
/// </summary>
[Test]
public void CanUseNamedThreads() {
using(new TestWorker("Test Task Thread")) { }
}
/// <summary>
/// Verifies that a background worker can be constructed that uses a fixed number
/// of threads using a specific name
/// </summary>
[Test]
public void CanUseFixedNumberOfNamedThreads() {
using(new TestWorker("Test Task Thread", 4)) { }
}
/// <summary>
/// Verifies that a background worker can be constructed that leaves free a fixed
/// number of CPU cores and uses a specific name for its worker threads.
/// </summary>
[Test]
public void CanPreserveFixedNumberOfCoresAndUseNamedThreads() {
using(new TestWorker("Test Task Thread", -2)) { }
}
/// <summary>
/// Verifies that exceptions happening inside the tasks are collected and re-thrown
/// in the Join() method.
/// </summary>
[Test]
public void ExceptionsAreReThrownInJoin() {
using(var testWorker = new TestWorker()) {
testWorker.ThrowException = true;
testWorker.AddTask(new object());
testWorker.AddTask(new object());
Assert.Throws<AggregateException>(
() => {
testWorker.Join();
}
);
try {
testWorker.Join();
Assert.Fail(
"Calling ParallelBackgroundWorker.Join() multiple times should re-throw " +
"exceptions multiple times"
);
}
catch(AggregateException aggregateException) {
Assert.AreEqual(2, aggregateException.InnerExceptions.Count);
}
}
}
/// <summary>
/// Verifies that tasks can be cancelled while they are running
/// </summary>
[Test]
public void TasksCanBeCancelled() {
using(var waitEvent = new ManualResetEvent(false)) {
using(var testWorker = new TestWorker()) {
testWorker.WaitEvent = waitEvent;
testWorker.AddTask(new object());
testWorker.CancelRunningTasks();
waitEvent.Set();
Assert.IsTrue(testWorker.Wait(1000));
Assert.IsTrue(testWorker.WasCancelled);
}
} // disposes waitEvent
}
/// <summary>Verifies that calling Join() waits for all queued tasks</summary>
[Test]
public void JoinWaitsForQueuedTasks() {
var tasks = new List<object>(100);
for(int index = 0; index < 100; ++index) {
tasks.Add(new object());
}
using(var waitEvent = new ManualResetEvent(false)) {
using(var testWorker = new TestWorker(2)) {
testWorker.WaitEvent = waitEvent;
testWorker.Tasks = new List<object>();
for(int index = 0; index < 100; ++index) {
testWorker.AddTask(tasks[index]);
}
CollectionAssert.IsEmpty(testWorker.Tasks);
waitEvent.Set();
testWorker.Join();
CollectionAssert.AreEquivalent(tasks, testWorker.Tasks);
}
} // disposes waitEvent
}
}
} // namespace Nuclex.Support
#endif // UNITTEST

104
Source/ParallelBackgroundWorker.cs
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@ -17,6 +17,12 @@ namespace Nuclex.Support {
public static readonly int Processors = Environment.ProcessorCount;
#endif
/// <summary>
/// Timeout after which Dispose() will stop waiting for unfinished tasks and
/// free resources anyway
/// </summary>
private static readonly int DefaultDisposeTimeoutMilliseconds = 1500; // milliseconds
/// <summary>Initializes a new parallel background worker with unlimited threads</summary>
public ParallelBackgroundWorker() : this(int.MaxValue) { }
@ -40,11 +46,12 @@ namespace Nuclex.Support {
threadCount = Math.Max(1, Processors + threadCount);
}
this.runQueuedTasksInThreadDelegate = new Action<object>(runQueuedTasksInThread);
this.runningThreads = new List<Task>();
this.queueSynchronizationRoot = new object();
this.runQueuedTasksInThreadDelegate = new Action(runQueuedTasksInThread);
this.tasks = new Queue<TTask>();
this.threadTerminatedEvent = new AutoResetEvent(false);
this.cancellationTokenSource = new CancellationTokenSource();
this.exceptions = new ConcurrentBag<Exception>();
}
/// <summary>
@ -81,7 +88,8 @@ namespace Nuclex.Support {
if(this.threadTerminatedEvent != null) {
CancelPendingTasks();
CancelRunningTasks();
Join();
Wait(DefaultDisposeTimeoutMilliseconds);
this.threadTerminatedEvent.Dispose();
this.threadTerminatedEvent = null;
@ -92,7 +100,6 @@ namespace Nuclex.Support {
}
}
/// <summary>Adds a task for processing by the background worker threads</summary>
/// <param name="task">Task that will be processed in the background</param>
public void AddTask(TTask task) {
@ -100,26 +107,28 @@ namespace Nuclex.Support {
return;
}
bool needNewThread;
lock(this.queueSynchronizationRoot) {
this.tasks.Enqueue(task);
if(this.runningThreads.Count < this.threadCount) {
//Task newThread = new Task(this.runQueuedTasksInThreadDelegate, );
needNewThread = (this.runningThreadCount < this.threadCount);
if(needNewThread) {
++this.runningThreadCount;
}
}
// Thread 1:
// lock() {
// - take task
// - or deregister and exit
// }
//
// Thread 2:
// lock() {
// - put task
// - if too few threads, register and add
// }
if(needNewThread) {
Task newThread = new Task(
this.runQueuedTasksInThreadDelegate,
// this.cancellationTokenSource.Token, // DO NOT PASS THIS!
// Passing the cancellation token makes tasks that have been queued but
// not started yet cease to execute at all - meaning our runningThreadCount
// goes out of sync and Dispose() / Wait() / Join() sit around endlessly!
TaskCreationOptions.LongRunning
);
newThread.Start();
}
}
/// <summary>Cancels all tasks that are currently executing</summary>
@ -134,11 +143,36 @@ namespace Nuclex.Support {
}
}
/// <summary>Waits until all executing and queued tasks have been processed</summary>
/// <summary>
/// Waits until all executing and queued tasks have been processed and throws an
/// exception if any errors have occurred
/// </summary>
public void Join() {
while(this.runningThreads.Count > 0) {
while(Thread.VolatileRead(ref this.runningThreadCount) > 0) {
this.threadTerminatedEvent.WaitOne();
}
if(this.exceptions.Count > 0) {
throw new AggregateException(this.exceptions);
}
}
/// <summary>
/// Waits until all executing and queued tasks have been processed or
/// the timeout is reached
/// </summary>
/// <param name="timeoutMilliseconds">Milliseconds after which the wait times out</param>
/// <returns>
/// True if all tasks have been processed, false if the timeout was reached
/// </returns>
public bool Wait(int timeoutMilliseconds) {
while(Thread.VolatileRead(ref this.runningThreadCount) > 0) {
if(this.threadTerminatedEvent.WaitOne(timeoutMilliseconds) == false) {
return false;
}
}
return true;
}
/// <summary>Called in a thread to execute a single task</summary>
@ -151,17 +185,23 @@ namespace Nuclex.Support {
/// <summary>
/// Runs queued tasks of the parallel background worker until the queue is empty
/// </summary>
/// <param name="thisTaskAsObject">Threading task in which this worker is running</param>
private void runQueuedTasksInThread(object thisTaskAsObject) {
private void runQueuedTasksInThread() {
string previousThreadName = null;
if(!string.IsNullOrEmpty(this.threadName)) {
previousThreadName = Thread.CurrentThread.Name;
Thread.CurrentThread.Name = this.threadName;
}
try {
#if false
for(;;) {
TTask task;
while(this.tasks.TryDequeue(out task)) {
lock(this.queueSynchronizationRoot) {
if(this.tasks.Count == 0) {
--this.runningThreadCount;
break;
}
task = this.tasks.Dequeue();
}
try {
Run(task, this.cancellationTokenSource.Token);
}
@ -170,11 +210,7 @@ namespace Nuclex.Support {
}
}
lock(this.runningThreads) {
this.runningThreads.Remove((Task)thisTaskAsObject);
}
this.threadTerminatedEvent.Set();
#endif
}
finally {
if(!string.IsNullOrEmpty(this.threadName)) {
@ -236,19 +272,11 @@ namespace Nuclex.Support {
private object queueSynchronizationRoot;
/// <summary>Delegate for the runQueuedTasksInThread() method</summary>
private Action<object> runQueuedTasksInThreadDelegate;
private Action runQueuedTasksInThreadDelegate;
/// <summary>Tasks remaining to be processed</summary>
private Queue<TTask> tasks;
/// <summary>Threads that are currently executing tasks</summary>
private IList<Task> runningThreads;
// Idea:
// private int runningThreadCount;
// Before the task looks for new work, it will decrement this
// if the task gets new work, it will increment this again.
// - if it would be above threadCount now, put work back in the queue
// AddTask() increments this after pushing new work
// - if it would be above threadCount, do not create a new thread
private int runningThreadCount;
/// <summary>Exceptions that have occurred while executing tasks</summary>
private ConcurrentBag<Exception> exceptions;