c# - Using async sockets on Windows Server 2008 R2 causes 100% CPU usage -

i have generic c# socket server uses asynchronous methods of socket classes - beginaccept(), beginreceive(), etc. server has been working great last 4 years @ many customer sites running win server 2003. installed on windows server 2008 r2 server, 64-bit. looks fine until first client connects , issues beginreceive() , beginaccept() call in accept handler. when happens, cpu usage spikes 100% , stays way until close listening socket.

not sure matters, server running in virtual machine.

have done lot of testing, nothing seems help. using process explorer, can see 2 threads spun shortly after beginreceive()/beginaccept() calls, , ones consuming processor. unfortunately, not able reproduce problem on win7 64-bit workstation.

i have done lot of research, , have found far following 2 kb articles imply server 2008 r2 may have issue tcp/ip components, available hot fixes: kb2465772 , kb2477730. reluctant have customer install them until more fix issue.

has else had problem? if so, did have resolve issue?

here method believe causes situation:

private void acceptcallback(iasyncresult result) {  connectioninfo connection = new connectioninfo();   try {     // finish accept.     socket listener = (socket)result.asyncstate;     connection.socket = listener.endaccept(result);     connection.request = new stringbuilder(256);      // start receive , new accept.     connection.socket.beginreceive(connection.buffer, 0,        connection.buffer.length, socketflags.none,        new asynccallback(receivecallback), connection);      _serversocket.beginaccept(new asynccallback(acceptcallback), listener);      // cpu usage spikes @ 100% shortly after this...   }  catch (objectdisposedexception /*ode*/) {     _log.debug("[acceptcallback] objectdisposedexception");  }  catch (socketexception se) {     connection.socket.close();     _log.errorformat("[acceptcallback] socket exception ({0}: {1} {2}", connection.clientaddress, se.errorcode, se.message);  }  catch (exception ex) {     connection.socket.close();     _log.errorformat("[acceptcallback] exception {0}: {1}", connection.clientaddress, ex.message);  } } 

the issue caused having more 1 call beginaccept() when setting listener socket. not know why problem occurs on 64bit servers, changing code shown below fixed issue.

original code:

public setupserversocket() {    ipendpoint myendpoint = new ipendpoint(ipaddress.any, _port);     // create socket, bind it, , start listening.   _serversocket = new socket(myendpoint.address.addressfamily, sockettype.stream, protocoltype.tcp);   _serversocket.bind(myendpoint);   _serversocket.listen((int)socketoptionname.maxconnections);    (int = 0; < 10; i++) {      _serversocket.beginaccept(new asynccallback(acceptcallback), _serversocket);   } } 

to following:

public setupserversocket() {    ipendpoint myendpoint = new ipendpoint(ipaddress.any, _port);     // create socket, bind it, , start listening.   _serversocket = new socket(myendpoint.address.addressfamily, sockettype.stream, protocoltype.tcp);   _serversocket.bind(myendpoint);   _serversocket.listen((int)socketoptionname.maxconnections);    //for (int = 0; < 10; i++) {      _serversocket.beginaccept(new asynccallback(acceptcallback), _serversocket);   //} }