Ayende @ Rahien

Ayende Rahien commented on High memory usage with WCF Discovery

Mon, 25 Jul 2011 15:19:00 GMT

Robert, I find it highly unlikely that a single ManualResetEvent would be that expensive.

Robert Slaney commented on High memory usage with WCF Discovery

Sun, 24 Jul 2011 23:11:41 GMT

Just looked through the System.ServiceModel.Discovery assembly using reflector and the Find method on DiscoveryClient instantiates a SyncOperationState object which internally contains ManualResetEvent. SyncOperationState class is internal but not disposable, and I cannot see anywhere that the ManualResetEvent is closed or disposed. I suppose the GC will eventually get around to collecting this but would definitely contribute to the excessive memory

Bertrand Le Roy commented on High memory usage with WCF Discovery

Sat, 23 Jul 2011 05:59:56 GMT

Just FYI, the post looks all funny in Google Reader, apparently doubly-encoded.

Ayende Rahien commented on High memory usage with WCF Discovery

Sat, 23 Jul 2011 02:25:32 GMT

That is very interesting, because it looks like most of the memory cost is actually on the Service Host, not on the DiscoverClient.

Ayende Rahien commented on High memory usage with WCF Discovery

Sat, 23 Jul 2011 02:23:50 GMT

Remco, I am probably going to try that next, yes. But I think that the actual cost is per connected server, need to check that further

Remco commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 21:59:20 GMT

It's probably the Binding buffer configuration. Using the below UdpDiscoveryEndpoint configuration for both service and client there is substantially less memory usage (from 170MB to 67MB maximum working set). Also, discovery is slower. var endpoint = new UdpDiscoveryEndpoint(); var binding = (CustomBinding)endpoint.Binding; var element = binding.Elements.OfType().First(); element.MaxBufferPoolSize = ushort.MaxValue; element.MaxReceivedMessageSize = ushort.MaxValue / 4; return endpoint;

Remco commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 20:49:59 GMT

Ah yes, well, can't help you there. apparently 640K is not enough for even 1 discoveryclient. Maybe it behaves better memorywise if just 1 discovery client with multiple async discoveries in flight is used instead of a whole bunch of clients? I am unfamiliar with System.ServiceModel.Discovery so I'm just guessing here.

Ayende Rahien commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 20:08:56 GMT

Remco, My problem isn't so much that this is a memory leak, my problem is that it is using _so much_ memory.

Remco commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 20:05:44 GMT

Last spam of the day, just edited the full repro to include an extra sleep of 60 seconds. Verdict: Select isn't broken, it's garbage collector is slow ;-)

Remco commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 19:49:07 GMT

It gets weirder, the results aren't consistent. only if I add this bit of code before the console.readkey I get a consistent drop of memory usage to about 40 MB Thread.Sleep(60000); PrintMemory("After sleep"); GC.Collect(); PrintMemory("After collect 2 "); GC.WaitForPendingFinalizers(); PrintMemory("After finalizers 2"); Console.ReadKey(); So my guess there's something fishy going on in the unmanaged world.

Remco commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 19:30:42 GMT

Maybe it's a debugger interaction. running the sample outside of the debugger got me these results with a debugger attached i got 209 for all the results. Before collect:209,000 After collect:40,000 After finalizers:40,000 so select isn't broken. the debugger is? full code: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; using System.ServiceModel.Discovery; using System.ServiceModel; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { int count = 150; var countdown = new CountdownEvent(count); for (int i = 0; i < count; i++) { var discoveryClient = new DiscoveryClient(new UdpDiscoveryEndpoint()); var findCriteria = new FindCriteria(typeof(IDiscoverableService)) { }; discoveryClient.FindProgressChanged += (sender, eventArgs) => { }; // do nothing discoveryClient.FindCompleted += (sender, eventArgs) => { using (discoveryClient) discoveryClient.Close(); PrintMemory(countdown.CurrentCount.ToString()); countdown.Signal(); }; discoveryClient.FindAsync(findCriteria); } countdown.Wait(); PrintMemory("Before collect"); GC.Collect(); PrintMemory("After collect"); GC.WaitForPendingFinalizers(); PrintMemory("After finalizers"); Console.ReadKey(); } private static void PrintMemory(string p) { Console.WriteLine("{0}:{1:N3}", p, Environment.WorkingSet / (1024 * 1024)); } } [ServiceContract] public interface IDiscoverableService { [OperationContract] void dosomething(); } }

Ayende Rahien commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 19:23:15 GMT

Kerry, I would hope so, I am disposing on it directly afterward, at any rate.

Kerry commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 19:20:44 GMT

This may be simplistic, but is the "discoveryClient.Find(findCriteria)" method disposing of its results after returning?

Ayende Rahien commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 18:38:51 GMT

Remco, Even so, 200MB still seems to be very excessive amount, no?

Remco commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 18:34:41 GMT

Really strange, the second example levels out at 210MB on my box (Vista 64bit), with no config of WCF whatsoever.

Ayende Rahien commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 18:23:07 GMT

Remco, I have done that with dotTrace, I can see that most of the memory is byte[], held by WCF, doesn't really help me figure out what is going on.

Remco commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 18:21:38 GMT

How about bringing out the big guns: procdump from sysinternals to make a dump, and windbg with the psscor4 extensions to show you where the memory has gone. ( with !dumpheap -stat )

Ayende Rahien commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 17:24:07 GMT

Saj, Nope, I am calling Close there.

Saj commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 17:22:31 GMT

I could be wrong but could you try using ( var discoveryClient = new DiscoveryClient(new UdpDiscoveryEndpoint()) ) { var findCriteria = new FindCriteria(typeof(IDiscoverableService)) { Duration = TimeSpan.FromSeconds(1) }; discoveryClient.Find(findCriteria); discoveryClient.Close(); }

Ayende Rahien commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 17:22:10 GMT

Vadim, Thanks, I wouldn't want you to "waste" this card unless you really don't have anything else to do with it.

Ayende Rahien commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 17:21:34 GMT

Jon, Interesting observation, and I tried playing with those values, but I don't think that this is it, I am seeing the same numbers, pretty much, even after limiting the max pool size to just 512 (bytes!).

Jon commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 16:06:15 GMT

Funny enough I was looking at this problem last week about wcf service holding onto large amounts of memory it turned out to be a simple configuration change to the setting maxBufferPoolSize. When you look at a lot of examples about sending large files etc through wcf services everyone blindly sets all the settings (maxBufferSize, maxReceivedMessageSize etc) to huge values and ussually the maxBufferPoolSize get set to the same huge value. However, this value indicates the pool size not a buffer size. so you want to limit your buffer pool to a number of cached buffers and not let it run wild. Set the maxBufferPoolSize to 1 just to test this theory and your memory usage should drop dramtically (if it is this!). I posted something on stackoverflow about this http://stackoverflow.com/questions/6713180/addressalreadyinuseexception-when-using-custombinding-but-not-when-using-nettcpbi/6720923#6720923 hope this helps!

Vadim commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 15:38:35 GMT

As an MS intern, I have an MS Q&A tech support card. Tell me if you need one :)

Ayende Rahien commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 14:28:20 GMT

Patric, But I am not holding any reference to the DiscoveryClient in the event handlers, or anywhere else.

Patric commented on High memory usage with WCF Discovery

Fri, 22 Jul 2011 11:52:25 GMT

Fore some time ago I have a problem with objects that was using events and the original object (discoveryClient) cant be released and disposed. The problem this time was that the object was only referenced by event-handler and because of that you have a reference to the object and the GC was not able to discard the object. After remove the event-handler after the object was used fixed my memory-leak problem.