public static void TestConcurrentExclusiveChain(bool syncContinuations)
{
var scheduler = new TrackingTaskScheduler(Environment.ProcessorCount);
var cesp = new ConcurrentExclusiveSchedulerPair(scheduler);
// continuations
{
var starter = new Task(() => { });
var t = starter;
for (int i = 0; i < 10; i++)
{
t = t.ContinueWith(delegate { }, CancellationToken.None, syncContinuations ? TaskContinuationOptions.ExecuteSynchronously : TaskContinuationOptions.None, cesp.ConcurrentScheduler);
t = t.ContinueWith(delegate { }, CancellationToken.None, syncContinuations ? TaskContinuationOptions.ExecuteSynchronously : TaskContinuationOptions.None, cesp.ExclusiveScheduler);
}
starter.Start(cesp.ExclusiveScheduler);
t.Wait();
}
// parent/child
{
var errorString = "hello faulty world";
var root = Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
throw new InvalidOperationException(errorString);
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ExclusiveScheduler).Wait();
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ExclusiveScheduler);
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ConcurrentScheduler);
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ExclusiveScheduler);
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ConcurrentScheduler);
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ExclusiveScheduler);
}, CancellationToken.None, TaskCreationOptions.None, cesp.ConcurrentScheduler);
((IAsyncResult)root).AsyncWaitHandle.WaitOne();
Assert.True(root.IsFaulted, "Root should have been faulted by child's error");
var ae = root.Exception.Flatten();
Assert.True(ae.InnerException is InvalidOperationException && ae.InnerException.Message == errorString,
"Child's exception should have propagated to the root.");
}
}
public static void TestLowerConcurrencyLevel()
{
//a custom scheduler with maxConcurrencyLevel of one
int customSchedulerConcurrency = 1;
TrackingTaskScheduler scheduler = new TrackingTaskScheduler(customSchedulerConcurrency);
// specify a maxConcurrencyLevel > TaskScheduler's maxconcurrencyLevel to ensure the pair takes the min of the two
ConcurrentExclusiveSchedulerPair schedPair = new ConcurrentExclusiveSchedulerPair(scheduler, int.MaxValue);
Assert.Equal(scheduler.MaximumConcurrencyLevel, schedPair.ConcurrentScheduler.MaximumConcurrencyLevel);
//Now schedule a reader task that would block and verify that more reader tasks scheduled are not executed
//(as long as the first task is blocked)
TaskFactory readers = new TaskFactory(schedPair.ConcurrentScheduler);
ManualResetEvent blockReaderTaskEvent = new ManualResetEvent(false);
ManualResetEvent blockMainThreadEvent = new ManualResetEvent(false);
//Add a reader tasks that would block
readers.StartNew(() => { blockMainThreadEvent.Set(); blockReaderTaskEvent.WaitOne(); });
blockMainThreadEvent.WaitOne(); // wait for the blockedTask to start execution
//Now add more reader tasks
int maxConcurrentTasks = Environment.ProcessorCount;
List <Task> taskList = new List <Task>();
for (int i = 0; i < maxConcurrentTasks; i++)
{
taskList.Add(readers.StartNew(() => { })); //schedule some dummy reader tasks
}
foreach (Task task in taskList)
{
bool wasTaskStarted = (task.Status != TaskStatus.Running) && (task.Status != TaskStatus.RanToCompletion);
Assert.True(wasTaskStarted, string.Format("Additional reader tasks should not start when scheduler concurrency is {0} and a reader task is blocked", customSchedulerConcurrency));
}
//finally unblock the blocjedTask and wait for all of the tasks, to ensure they all executed properly
blockReaderTaskEvent.Set();
Task.WaitAll(taskList.ToArray());
}
public static void TestMaxItemsPerTask(int maxConcurrency, int maxItemsPerTask, bool completeBeforeTaskWait)
{
//Create a custom TaskScheduler with specified max concurrency (TrackingTaskScheduler is defined in Common\tools\CommonUtils\TPLTestSchedulers.cs)
TrackingTaskScheduler scheduler = new TrackingTaskScheduler(maxConcurrency);
//We need to use the custom scheduler to achieve the results. As a by-product, we test to ensure custom schedulers are supported
ConcurrentExclusiveSchedulerPair schedPair = new ConcurrentExclusiveSchedulerPair(scheduler, maxConcurrency, maxItemsPerTask);
TaskFactory readers = new TaskFactory(schedPair.ConcurrentScheduler); //get reader and writer schedulers
TaskFactory writers = new TaskFactory(schedPair.ExclusiveScheduler);
//These are threadlocals to ensure that no concurrency side effects occur
ThreadLocal <int> itemsExecutedCount = new ThreadLocal <int>(); //Track the items executed by CEScheduler Task
ThreadLocal <int> schedulerIDInsideTask = new ThreadLocal <int>(); //Used to store the Scheduler ID observed by a Task Executed by CEScheduler Task
//Work done by both reader and writer tasks
Action work = () =>
{
//Get the id of the parent Task (which is the task created by the scheduler). Each task run by the scheduler task should
//see the same SchedulerID value since they are run on the same thread
int id = ((TrackingTaskScheduler)scheduler).SchedulerID.Value;
if (id == schedulerIDInsideTask.Value)
{ //since ids match, this is one more Task being executed by the CEScheduler Task
itemsExecutedCount.Value = ++itemsExecutedCount.Value;
//This does not need to be thread safe since we are looking to ensure that only n number of tasks were executed and not the order
//in which they were executed. Also asserting inside the thread is fine since we just want the test to be marked as failure
Assert.True(itemsExecutedCount.Value <= maxItemsPerTask, string.Format("itemsExecutedCount={0} cant be greater than maxValue={1}. Parent TaskID={2}",
itemsExecutedCount, maxItemsPerTask, id));
}
else
{ //Since ids don't match, this is the first Task being executed in the CEScheduler Task
schedulerIDInsideTask.Value = id; //cache the scheduler ID seen by the thread, so other tasks running in same thread can see this
itemsExecutedCount.Value = 1;
}
//Give enough time for a Task to stay around, so that other tasks will be executed by the same CEScheduler Task
//or else the CESchedulerTask will die and each Task might get executed by a different CEScheduler Task. This does not affect the
//verifications, but its increases the chance of finding a bug if the maxItemPerTask is not respected
new ManualResetEvent(false).WaitOne(1);
};
List <Task> taskList = new List <Task>();
int maxConcurrentTasks = maxConcurrency * maxItemsPerTask * 5;
int maxExclusiveTasks = maxConcurrency * maxItemsPerTask * 2;
// Schedule Tasks in both concurrent and exclusive mode
for (int i = 0; i < maxConcurrentTasks; i++)
{
taskList.Add(readers.StartNew(work));
}
for (int i = 0; i < maxExclusiveTasks; i++)
{
taskList.Add(writers.StartNew(work));
}
if (completeBeforeTaskWait)
{
schedPair.Complete();
schedPair.Completion.Wait();
Assert.True(taskList.TrueForAll(t => t.IsCompleted), "All tasks should have completed for scheduler to complete");
}
//finally wait for all of the tasks, to ensure they all executed properly
Task.WaitAll(taskList.ToArray());
if (!completeBeforeTaskWait)
{
schedPair.Complete();
schedPair.Completion.Wait();
Assert.True(taskList.TrueForAll(t => t.IsCompleted), "All tasks should have completed for scheduler to complete");
}
}
public static void TestConcurrentExclusiveChain(bool syncContinuations)
{
var scheduler = new TrackingTaskScheduler(Environment.ProcessorCount);
var cesp = new ConcurrentExclusiveSchedulerPair(scheduler);
// continuations
{
var starter = new Task(() => { });
var t = starter;
for (int i = 0; i < 10; i++)
{
t = t.ContinueWith(delegate { }, CancellationToken.None, syncContinuations ? TaskContinuationOptions.ExecuteSynchronously : TaskContinuationOptions.None, cesp.ConcurrentScheduler);
t = t.ContinueWith(delegate { }, CancellationToken.None, syncContinuations ? TaskContinuationOptions.ExecuteSynchronously : TaskContinuationOptions.None, cesp.ExclusiveScheduler);
}
starter.Start(cesp.ExclusiveScheduler);
t.Wait();
}
// parent/child
{
var errorString = "hello faulty world";
var root = Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
Task.Factory.StartNew(() =>
{
throw new InvalidOperationException(errorString);
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ExclusiveScheduler).Wait();
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ExclusiveScheduler);
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ConcurrentScheduler);
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ExclusiveScheduler);
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ConcurrentScheduler);
}, CancellationToken.None, TaskCreationOptions.AttachedToParent, cesp.ExclusiveScheduler);
}, CancellationToken.None, TaskCreationOptions.None, cesp.ConcurrentScheduler);
((IAsyncResult)root).AsyncWaitHandle.WaitOne();
Assert.True(root.IsFaulted, "Root should have been faulted by child's error");
var ae = root.Exception.Flatten();
Assert.True(ae.InnerException is InvalidOperationException && ae.InnerException.Message == errorString,
"Child's exception should have propagated to the root.");
}
}
public static void TestLowerConcurrencyLevel()
{
//a custom scheduler with maxConcurrencyLevel of one
int customSchedulerConcurrency = 1;
TrackingTaskScheduler scheduler = new TrackingTaskScheduler(customSchedulerConcurrency);
// specify a maxConcurrencyLevel > TaskScheduler's maxconcurrencyLevel to ensure the pair takes the min of the two
ConcurrentExclusiveSchedulerPair schedPair = new ConcurrentExclusiveSchedulerPair(scheduler, Int32.MaxValue);
Assert.Equal(scheduler.MaximumConcurrencyLevel, schedPair.ConcurrentScheduler.MaximumConcurrencyLevel);
//Now schedule a reader task that would block and verify that more reader tasks scheduled are not executed
//(as long as the first task is blocked)
TaskFactory readers = new TaskFactory(schedPair.ConcurrentScheduler);
ManualResetEvent blockReaderTaskEvent = new ManualResetEvent(false);
ManualResetEvent blockMainThreadEvent = new ManualResetEvent(false);
//Add a reader tasks that would block
readers.StartNew(() => { blockMainThreadEvent.Set(); blockReaderTaskEvent.WaitOne(); });
blockMainThreadEvent.WaitOne(); // wait for the blockedTask to start execution
//Now add more reader tasks
int maxConcurrentTasks = Environment.ProcessorCount;
List<Task> taskList = new List<Task>();
for (int i = 0; i < maxConcurrentTasks; i++)
taskList.Add(readers.StartNew(() => { })); //schedule some dummy reader tasks
foreach (Task task in taskList)
{
bool wasTaskStarted = (task.Status != TaskStatus.Running) && (task.Status != TaskStatus.RanToCompletion);
Assert.True(wasTaskStarted, string.Format("Additional reader tasks should not start when scheduler concurrency is {0} and a reader task is blocked", customSchedulerConcurrency));
}
//finally unblock the blocjedTask and wait for all of the tasks, to ensure they all executed properly
blockReaderTaskEvent.Set();
Task.WaitAll(taskList.ToArray());
}
public static void TestMaxItemsPerTask(int maxConcurrency, int maxItemsPerTask, bool completeBeforeTaskWait)
{
//Create a custom TaskScheduler with specified max concurrency (TrackingTaskScheduler is defined in Common\tools\CommonUtils\TPLTestSchedulers.cs)
TrackingTaskScheduler scheduler = new TrackingTaskScheduler(maxConcurrency);
//We need to use the custom scheduler to achieve the results. As a by-product, we test to ensure custom schedulers are supported
ConcurrentExclusiveSchedulerPair schedPair = new ConcurrentExclusiveSchedulerPair(scheduler, maxConcurrency, maxItemsPerTask);
TaskFactory readers = new TaskFactory(schedPair.ConcurrentScheduler); //get reader and writer schedulers
TaskFactory writers = new TaskFactory(schedPair.ExclusiveScheduler);
//These are threadlocals to ensure that no concurrency side effects occur
ThreadLocal<int> itemsExecutedCount = new ThreadLocal<int>(); //Track the items executed by CEScheduler Task
ThreadLocal<int> schedulerIDInsideTask = new ThreadLocal<int>(); //Used to store the Scheduler ID observed by a Task Executed by CEScheduler Task
//Work done by both reader and writer tasks
Action work = () =>
{
//Get the id of the parent Task (which is the task created by the scheduler). Each task run by the scheduler task should
//see the same SchedulerID value since they are run on the same thread
int id = ((TrackingTaskScheduler)scheduler).SchedulerID.Value;
if (id == schedulerIDInsideTask.Value)
{ //since ids match, this is one more Task being executed by the CEScheduler Task
itemsExecutedCount.Value = ++itemsExecutedCount.Value;
//This does not need to be thread safe since we are looking to ensure that only n number of tasks were executed and not the order
//in which they were executed. Also asserting inside the thread is fine since we just want the test to be marked as failure
Assert.True(itemsExecutedCount.Value <= maxItemsPerTask, string.Format("itemsExecutedCount={0} cant be greater than maxValue={1}. Parent TaskID={2}",
itemsExecutedCount, maxItemsPerTask, id));
}
else
{ //Since ids dont match, this is the first Task being executed in the CEScheduler Task
schedulerIDInsideTask.Value = id; //cache the scheduler ID seen by the thread, so other tasks running in same thread can see this
itemsExecutedCount.Value = 1;
}
//Give enough time for a Task to stay around, so that other tasks will be executed by the same CEScheduler Task
//or else the CESchedulerTask will die and each Task might get executed by a different CEScheduler Task. This does not affect the
//verifications, but its increases the chance of finding a bug if the maxItemPerTask is not respected
new ManualResetEvent(false).WaitOne(20);
};
List<Task> taskList = new List<Task>();
int maxConcurrentTasks = maxConcurrency * maxItemsPerTask * 5;
int maxExclusiveTasks = maxConcurrency * maxItemsPerTask * 2;
// Schedule Tasks in both concurrent and exclusive mode
for (int i = 0; i < maxConcurrentTasks; i++)
taskList.Add(readers.StartNew(work));
for (int i = 0; i < maxExclusiveTasks; i++)
taskList.Add(writers.StartNew(work));
if (completeBeforeTaskWait)
{
schedPair.Complete();
schedPair.Completion.Wait();
Assert.True(taskList.TrueForAll(t => t.IsCompleted), "All tasks should have completed for scheduler to complete");
}
//finally wait for all of the tasks, to ensure they all executed properly
Task.WaitAll(taskList.ToArray());
if (!completeBeforeTaskWait)
{
schedPair.Complete();
schedPair.Completion.Wait();
Assert.True(taskList.TrueForAll(t => t.IsCompleted), "All tasks should have completed for scheduler to complete");
}
}
