OutOfMemoryException running published Rx performance test

Question

Hi,

I'm following along in Bart's article from March this year on Rx 2.0 enhancements.

http://blogs.msdn.com/b/rxteam/archive/2012/03/12/reactive-extensions-v2-0-beta-available-now.aspx

I tried running one of the performance tests using Rx 2.0 RTM and .NET Framework 4.0, and encountered an OutOfMemoryException. Specifically, I tried this test:

static void Survival<TFittest>()
{
    var xs = new Fast().Delay(TimeSpan.FromSeconds(5));

    var c = new Count<int>();

    var sw = Stopwatch.StartNew();
    using (xs.Subscribe(c))
        Thread.Sleep(30000);
    sw.Stop();

    Console.WriteLine(c.Total / sw.Elapsed.TotalSeconds + " msgs/s");
}

This is supposed to be a test of memory allocation related to the Delay operator. When I run this program, I get an OutOfMemoryException within a couple seconds.

Anyone have an idea why this might be happening? My machine is running at 5.46GB right now. I have 8GB of RAM. When I start the process, memory grows to 6.22GB and then the process dies.

Interesting if I change the delay to 1 ms, I still get an OutOfMemoryException.

Any ideas why this is happening?

Thanks,
Ranjith

Answer 1

Hi Ranjith,

I can't reproduce the problem with .NET 4.5.  I didn't try with .NET 4.0 though.  Maybe you could try against .NET 4.5?

I just tested against Rx 2.0.21103.1 (assembly version 2.0.20823.0) for .NET 4.5.  After running the test 3 times in a row, to warm up caches, here were the final results:

110527.702672517 msgs/s

Memory <= 600 MB
~2 garbage collections

My computer: 

Windows 8 Pro, x64
Intel(R) Xeon(TM) CPU 3.40GHz, 3391 Mhz, 1 Core(s), 2 Logical Processor(s)
Installed Physical Memory (RAM) 4.00 GB
Available Physical Memory 1.91 GB

Here is the complete code, taken from the Rx Team's blog post:

Note: I've changed it slightly to run inside of a lab application, so technically the code was hosted in a WPF UserControl instead of a console window during my tests, though I suspect that if I were to run a pure console app the results would be the same.

using System;
using System.Diagnostics;
using System.Reactive.Disposables;
using System.Reactive.Linq;
using System.Threading;

namespace Rxx.Labs.Performance
{
	public sealed class DelayThroughputLab : BaseConsoleLab
	{
		protected override void Main()
		{
			var xs = new Fast().Delay(TimeSpan.FromSeconds(5));

			var c = new Count<int>();

			var sw = Stopwatch.StartNew();
			using (xs.Subscribe(c))
				Thread.Sleep(30000);
			sw.Stop();

			TraceLine(c.Total / sw.Elapsed.TotalSeconds + " msgs/s");
		}

		class Count<T> : IObserver<T>
		{
			public int Total;

			public void OnNext(T value)
			{
				Total++;
			}

			public void OnError(Exception error)
			{
				throw new NotImplementedException();
			}

			public void OnCompleted()
			{
				throw new NotImplementedException();
			}
		}

		class Fast : IObservable<int>
		{
			public IDisposable Subscribe(IObserver<int> observer)
			{
				var d = new BooleanDisposable();

				new Thread(() =>
				{
					while (!d.IsDisposed)
						observer.OnNext(42);
				}).Start();

				return d;
			}
		}
	}
}

- Dave

---

http://davesexton.com/blog

Answer 2

Hi Ranjith,

I just tested in a console app targeting .NET 4.0 and I still couldn't reproduce your error.  The results were similar to my previous test targeting .NET 4.5.

- Dave

---

http://davesexton.com/blog

Answer 3

Hmmm. Thanks for testing, Dave. I'm not sure what I'm doing wrong. I created a console app targeting .NET Framework 4, and I'm running it on Windows 7 Enterprise.  I tried compiling the app as 64 bit, but that didn't help.

Here's my exact code:

namespace Performance
{
class Program
{
static void Main(string[] args)
{
var xs = new Fast().Delay(TimeSpan.FromSeconds(5));

var c = new Count<int>();

var sw = Stopwatch.StartNew();
using (xs.Subscribe(c))
Thread.Sleep(30000);
sw.Stop();

Console.WriteLine(c.Total / sw.Elapsed.TotalSeconds + " msgs/s");
}

class Count<T> : IObserver<T>
{
public int Total;

public void OnNext(T value)
{
Total++;
}

public void OnError(Exception error)
{
throw new NotImplementedException();
}

public void OnCompleted()
{
throw new NotImplementedException();
}
}

class Fast : IObservable<int>
{
public IDisposable Subscribe(IObserver<int> observer)
{
var d = new BooleanDisposable();

new Thread(() =>
{
while (!d.IsDisposed)
observer.OnNext(42);
}).Start();

return d;
}
}
}
}

Answer 4

Hi Ranjith,

Have you tried running a profiler such as Visual Studio, PerfView or CLRProfiler?  Perhaps it would be useful to see the actual allocations and the hot execution path.

- Dave

---

http://davesexton.com/blog

Answer 5

Hi Ranjith,

Just to be clear, have you updated to the latest version of Rx 2.0?  You can download it from NuGet.  This is the version that I used when testing.

- Dave

---

http://davesexton.com/blog