Bug 1653 - ThreadPool QueueUserWorkItem is slow
Summary: ThreadPool QueueUserWorkItem is slow
Alias: None
Product: Runtime
Classification: Mono
Component: General ()
Version: unspecified
Hardware: PC Linux
: --- normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2011-10-23 14:14 UTC by Marek Safar
Modified: 2017-07-11 21:13 UTC (History)
3 users (show)

Is this bug a regression?: ---
Last known good build:

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Description Marek Safar 2011-10-23 14:14:37 UTC
using System;
using System.Threading;
using System.Diagnostics;

class MyContext
	public static void Main ()
		int counter = 0;
		const int iter = 10000000;

		var sw = new Stopwatch ();
		sw.Start ();
		for (int i = 0; i < iter; ++i) {
			ThreadPool.QueueUserWorkItem (delegate { Interlocked.Increment (ref counter); });
		Console.WriteLine (sw.ElapsedMilliseconds);
		SpinWait.SpinUntil (() => counter == iter);
		Console.WriteLine (sw.ElapsedMilliseconds);

Mono on amd64 8 cores

.NET on amd64 4 cores
Comment 1 Gonzalo Paniagua Javier 2011-10-23 23:15:06 UTC
The different with .NET is big, but if you compare it to mono 2.6, we are 10-15x faster...

The problem with this kind of micro test is the way we store the work items, which involves dynamically allocating lists of arrays that are managed by the GC.

I have no idea of what to do next.
Comment 2 Marek Safar 2011-10-26 05:53:35 UTC
One option would be to not allocate System.Runtime.Remoting.Messaging.AsyncResult or reduce its size if the allocation cannot be avoided
Comment 3 Rodrigo Kumpera 2017-07-11 21:13:40 UTC
We use the same TP as dotnet now.