Clarification on running multiple async tasks in parallel with throttling and polly policies
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I'm trying to run multiple async Tasks in parallel with throttling using polly AsyncBulkheadPolicy + WaitAndRetryPolicy. My understanding so far is that the policy method ExecuteAsync does not itself make a call onto a thread, but is leaving that to the default Task Scheduler or someone before it. Thus, if my tasks are CPU bound in some way then I need to use Parallel.ForEach when executing tasks or Task.Run() with the ExecuteAsync method in order to schedule the tasks to background threads.
Can someone look at the examples below and clarify how they would work in terms of parallism and threadpooling? What they would suggest?
https://github.com/App-vNext/Polly/wiki/Bulkhead - Operation: The policy itself does not place calls onto threads; it assumes upstream systems have already placed calls into threads, but limits their parallelization of execution.
async Task DoSomething(IEnumerable<object> objects);
//Example 1:
//Simple use, but then I don't have access to retry policies from polly
Parallel.ForEach(groupedObjects, (set) =>
{
var task = DoSomething(set);
task.Wait();
});
//Example 2:
//Uses default TaskScheduler which may or may not run the tasks in parallel
var parallelTasks = new List<Task>();
foreach (var set in groupedObjects)
{
var task = bulkheadPolicy.ExecuteAsync(async () => DoSomething(set));
parallelTasks.Add(task);
};
await Task.WhenAll(parallelTasks);
//Example 3:
//seems to defeat the purpose of the bulkhead since Parallel.ForEach and
//PolicyBulkheadAsync can both do throttling...just use basic RetryPolicy
//here?
Parallel.ForEach(groupedObjects, (set) =>
{
var task = policy.ExecuteAsync(async () => DoSomething(set));
task.Wait();
});
//Example 4:
//Task.Run still uses the default Task Scheduler and isn't any different than
//Example 2; just makes more tasks (wrapping the async tasks)
var parallelTasks = new List<Task>();
foreach (var set in groupedObjects)
{
var task = Task.Run(async () => await bulkheadPolicy.ExecuteAsync(async () => DoSomething(set)));
parallelTasks.Add(task);
};
await Task.WhenAll(parallelTasks);
DoSomething is an async method doing operations on a set of objects, it's both I/O and CPU bound. I'd like this to happen in parallel threads while respecting retry policies from polly and allowing for throttling.
I seem to have confused myself along the way in what exactly the functional behavior of Parallel.ForEach and using Bulkhead.ExecuteAsync does, however, when it comes to how tasks/threads are handled.
I'm leaning towards example 3 or a tweaked 4 (Task.Run + ConfigureAwait(false) should net me different threadpool threads, yes?)
c# performance multithreading asynchronous task-parallel-library
asked 1 hour ago
Jonathan AllbrittenJonathan Allbritten
61
New contributor
Jonathan Allbritten is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
I'm trying to run multiple async Tasks in parallel with throttling using polly AsyncBulkheadPolicy + WaitAndRetryPolicy. My understanding so far is that the policy method ExecuteAsync does not itself make a call onto a thread, but is leaving that to the default Task Scheduler or someone before it. Thus, if my tasks are CPU bound in some way then I need to use Parallel.ForEach when executing tasks or Task.Run() with the ExecuteAsync method in order to schedule the tasks to background threads.
Can someone look at the examples below and clarify how they would work in terms of parallism and threadpooling? What they would suggest?
https://github.com/App-vNext/Polly/wiki/Bulkhead - Operation: The policy itself does not place calls onto threads; it assumes upstream systems have already placed calls into threads, but limits their parallelization of execution.
async Task DoSomething(IEnumerable<object> objects);
//Example 1:
//Simple use, but then I don't have access to retry policies from polly
Parallel.ForEach(groupedObjects, (set) =>
{
var task = DoSomething(set);
task.Wait();
});
//Example 2:
//Uses default TaskScheduler which may or may not run the tasks in parallel
var parallelTasks = new List<Task>();
foreach (var set in groupedObjects)
{
var task = bulkheadPolicy.ExecuteAsync(async () => DoSomething(set));
parallelTasks.Add(task);
};
await Task.WhenAll(parallelTasks);
//Example 3:
//seems to defeat the purpose of the bulkhead since Parallel.ForEach and
//PolicyBulkheadAsync can both do throttling...just use basic RetryPolicy
//here?
Parallel.ForEach(groupedObjects, (set) =>
{
var task = policy.ExecuteAsync(async () => DoSomething(set));
task.Wait();
});
//Example 4:
//Task.Run still uses the default Task Scheduler and isn't any different than
//Example 2; just makes more tasks (wrapping the async tasks)
var parallelTasks = new List<Task>();
foreach (var set in groupedObjects)
{
var task = Task.Run(async () => await bulkheadPolicy.ExecuteAsync(async () => DoSomething(set)));
parallelTasks.Add(task);
};
await Task.WhenAll(parallelTasks);
DoSomething is an async method doing operations on a set of objects, it's both I/O and CPU bound. I'd like this to happen in parallel threads while respecting retry policies from polly and allowing for throttling.
I seem to have confused myself along the way in what exactly the functional behavior of Parallel.ForEach and using Bulkhead.ExecuteAsync does, however, when it comes to how tasks/threads are handled.
I'm leaning towards example 3 or a tweaked 4 (Task.Run + ConfigureAwait(false) should net me different threadpool threads, yes?)
c# performance multithreading asynchronous task-parallel-library
asked 1 hour ago
Jonathan AllbrittenJonathan Allbritten
61
New contributor
Jonathan Allbritten is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
I'm trying to run multiple async Tasks in parallel with throttling using polly AsyncBulkheadPolicy + WaitAndRetryPolicy. My understanding so far is that the policy method ExecuteAsync does not itself make a call onto a thread, but is leaving that to the default Task Scheduler or someone before it. Thus, if my tasks are CPU bound in some way then I need to use Parallel.ForEach when executing tasks or Task.Run() with the ExecuteAsync method in order to schedule the tasks to background threads.
Can someone look at the examples below and clarify how they would work in terms of parallism and threadpooling? What they would suggest?
https://github.com/App-vNext/Polly/wiki/Bulkhead - Operation: The policy itself does not place calls onto threads; it assumes upstream systems have already placed calls into threads, but limits their parallelization of execution.
async Task DoSomething(IEnumerable<object> objects);
//Example 1:
//Simple use, but then I don't have access to retry policies from polly
Parallel.ForEach(groupedObjects, (set) =>
{
var task = DoSomething(set);
task.Wait();
});
//Example 2:
//Uses default TaskScheduler which may or may not run the tasks in parallel
var parallelTasks = new List<Task>();
foreach (var set in groupedObjects)
{
var task = bulkheadPolicy.ExecuteAsync(async () => DoSomething(set));
parallelTasks.Add(task);
};
await Task.WhenAll(parallelTasks);
//Example 3:
//seems to defeat the purpose of the bulkhead since Parallel.ForEach and
//PolicyBulkheadAsync can both do throttling...just use basic RetryPolicy
//here?
Parallel.ForEach(groupedObjects, (set) =>
{
var task = policy.ExecuteAsync(async () => DoSomething(set));
task.Wait();
});
//Example 4:
//Task.Run still uses the default Task Scheduler and isn't any different than
//Example 2; just makes more tasks (wrapping the async tasks)
var parallelTasks = new List<Task>();
foreach (var set in groupedObjects)
{
var task = Task.Run(async () => await bulkheadPolicy.ExecuteAsync(async () => DoSomething(set)));
parallelTasks.Add(task);
};
await Task.WhenAll(parallelTasks);
DoSomething is an async method doing operations on a set of objects, it's both I/O and CPU bound. I'd like this to happen in parallel threads while respecting retry policies from polly and allowing for throttling.
I seem to have confused myself along the way in what exactly the functional behavior of Parallel.ForEach and using Bulkhead.ExecuteAsync does, however, when it comes to how tasks/threads are handled.
I'm leaning towards example 3 or a tweaked 4 (Task.Run + ConfigureAwait(false) should net me different threadpool threads, yes?)
c# performance multithreading asynchronous task-parallel-library
asked 1 hour ago
Jonathan AllbrittenJonathan Allbritten
61
New contributor
Jonathan Allbritten is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I'm trying to run multiple async Tasks in parallel with throttling using polly AsyncBulkheadPolicy + WaitAndRetryPolicy. My understanding so far is that the policy method ExecuteAsync does not itself make a call onto a thread, but is leaving that to the default Task Scheduler or someone before it. Thus, if my tasks are CPU bound in some way then I need to use Parallel.ForEach when executing tasks or Task.Run() with the ExecuteAsync method in order to schedule the tasks to background threads.
Can someone look at the examples below and clarify how they would work in terms of parallism and threadpooling? What they would suggest?
https://github.com/App-vNext/Polly/wiki/Bulkhead - Operation: The policy itself does not place calls onto threads; it assumes upstream systems have already placed calls into threads, but limits their parallelization of execution.
async Task DoSomething(IEnumerable<object> objects);
//Example 1:
//Simple use, but then I don't have access to retry policies from polly
Parallel.ForEach(groupedObjects, (set) =>
{
var task = DoSomething(set);
task.Wait();
});
//Example 2:
//Uses default TaskScheduler which may or may not run the tasks in parallel
var parallelTasks = new List<Task>();
foreach (var set in groupedObjects)
{
var task = bulkheadPolicy.ExecuteAsync(async () => DoSomething(set));
parallelTasks.Add(task);
};
await Task.WhenAll(parallelTasks);
//Example 3:
//seems to defeat the purpose of the bulkhead since Parallel.ForEach and
//PolicyBulkheadAsync can both do throttling...just use basic RetryPolicy
//here?
Parallel.ForEach(groupedObjects, (set) =>
{
var task = policy.ExecuteAsync(async () => DoSomething(set));
task.Wait();
});
//Example 4:
//Task.Run still uses the default Task Scheduler and isn't any different than
//Example 2; just makes more tasks (wrapping the async tasks)
var parallelTasks = new List<Task>();
foreach (var set in groupedObjects)
{
var task = Task.Run(async () => await bulkheadPolicy.ExecuteAsync(async () => DoSomething(set)));
parallelTasks.Add(task);
};
await Task.WhenAll(parallelTasks);
DoSomething is an async method doing operations on a set of objects, it's both I/O and CPU bound. I'd like this to happen in parallel threads while respecting retry policies from polly and allowing for throttling.
I seem to have confused myself along the way in what exactly the functional behavior of Parallel.ForEach and using Bulkhead.ExecuteAsync does, however, when it comes to how tasks/threads are handled.
I'm leaning towards example 3 or a tweaked 4 (Task.Run + ConfigureAwait(false) should net me different threadpool threads, yes?)
c# performance multithreading asynchronous task-parallel-library
c# performance multithreading asynchronous task-parallel-library
asked 1 hour ago
Jonathan AllbrittenJonathan Allbritten
61
New contributor
Jonathan Allbritten is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 1 hour ago
Jonathan AllbrittenJonathan Allbritten
61
New contributor
Jonathan Allbritten is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 1 hour ago
Jonathan AllbrittenJonathan Allbritten
61
New contributor
Jonathan Allbritten is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 1 hour ago
Jonathan AllbrittenJonathan Allbritten
61
asked 1 hour ago
Jonathan AllbrittenJonathan Allbritten
61
61
New contributor
Jonathan Allbritten is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Jonathan Allbritten is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Jonathan Allbritten is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
add a comment |
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