[Mono-list] Async sockets and memory leaks in BeginSend

[Rolf Bjarne Kvinge]

Hi,

Which version of Mono are you using? I believe this particular scenario has
been improved a lot in mono master, so can you try that if you're not
already using it?

Rolf

On Mon, May 21, 2012 at 10:51 PM, xplicit <svg at ngs.ru> wrote:

> I am developing server with mono using async socket model. Currently it's
> about 500 simultaneously working clients with 20-100 operations per
> seconds.
> The code should send messages accordingly theirs creation time, so I use
> such pattern:
>
> Send()
> {
>    //Dequeue message from queue. Messages placed in the queue accordingly
> theirs creation time
>    SendStateObject state=new SendStateObject();
>    state.buffer=Dequeue();
>    state.socket=client;
>
>    //some checks in the code were removed, this function is called only
> when no other send callbacks were ran
>    client.BeginSend(state.buffer, 0, state.buffer.Length, SocketFlags.None,
> new AsyncCallback(SendCallback), state);
>
> }
>
> private void SendCallback(IAsyncResult ar)
> {
>    SendStateObject sendState = (SendStateObject)ar.AsyncState;
>    Socket client = sendState.workSocket;
>
>    try
>    {
>          client.EndSend(ar);
>    }
>    catch() /*Some exceptions handling */
>    {}
>    finally
>    {
>          sendState.buffer=null;
>          sendState.workSocket=null;
>    }
>
>    if (SomeItemsInQueue()) Send();
>
> }
>
> And this code produces huge memory leaks under high load. Profiler says,
> that there are millions of AsyncCallback objects and
> System.Net.Sockets.SocketAsyncResult objects.
>
> I think, I could minimize number of AsyncCallback objects by creating it
> only one time in constructor and passing it to BeginSend (I'll check it
> later), but what to do with SocketAsyncResult (and byte buffers which it
> contains in)?
> I don't create this object, it's created inside of BeginSend and in most
> cases it is not claimed by garbage collector.
>
> Maybe I use wrong pattern and must remove calling Send() from the end line
> of callback, but I don't understand, why these objects could not be freed
> by
> GC...
>
>
>
> --
> View this message in context:
> http://mono.1490590.n4.nabble.com/Async-sockets-and-memory-leaks-in-BeginSend-tp4648844.html
> Sent from the Mono - General mailing list archive at Nabble.com.
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