Socket communication very slow on Mac OS X 10.6

Question

Hi everybody,
I'm using a socket based communication in an application and in Mac OS 10.5 everything works quick and flawless using XCode 3.1.4.
In Mac OS 10. 6, using XCode 3.2.4, I set the Mac OS X 10.6 SDK, I recompiled the app. but the responsiveness of the app is terrible slow. The GUI itself runs OK but any socket related action is painfully slow (sometimes connection timeout).
The socket communication is implemented using standard CFSocket classes.
Is this a XCode migration issue from 3.1 to 3.2 or a Mac OS 10.6 related one (I've seen lots of complains on networking issues)?
Thank you very much,
Dan

Answer 1

Thank you very much for the info but why it worked (and really fast) on 10.5. I also wonder why I didn't run into TCP_NODELAY problem there ? My TCP buffer size is 1K and I'm using the same testing environment.
Of course there is much more to it than some init parameters but still, what could be so different on 10.6 ? And I tried already the sysctl.conf TCP_NODELAY setting but no effect.
This is the code (briefly):
1. CONNECT
// Create signature from ip and port
struct sockaddr_in sin; /* TCP/UDP socket address structure. */
self->m_RemoteSocketSignature = (CFSocketSignature*)malloc(sizeof(CFSocketSignature));
self->m_RemoteSocketSignature->protocolFamily = PF_INET; /* IPv4 */
self->m_RemoteSocketSignature->socketType = SOCK_STREAM; /* Stream oriented. */
self->m_RemoteSocketSignature->protocol = IPPROTO_TCP; /* TCP */
memset( &sin, 0, sizeof( sin ) );
sin.sin_len= sizeof( sin );
sin.sin_family = AF_INET; /* Address is IPv4. Use PF_xxx for protocol
description, AF_xxx for address description. */
/* sin.port and sin.addr are in network( big endian ) byte order. */
sin.sin_port = CFSwapInt16HostToBig( port );
inet_aton( [address UTF8String], &sin.sin_addr ); /* inet_aton() gives back
network order addresses from strings. */
self->m_RemoteSocketSignature->address = CFDataCreate( NULL, (UInt8 *)&sin, sizeof( sin ) );
// Connect the Write & the Read streams to the socket
CFStreamCreatePairWithPeerSocketSignature (
kCFAllocatorDefault,
m_RemoteSocketSignature,
& m_ReadStream,
& m_WriteStream
if((m_ReadStream != NULL) && (m_WriteStream != NULL))
bOpenWrite = CFWriteStreamOpen (m_WriteStream);
bOpenRead = CFReadStreamOpen (m_ReadStream);
2. RECEIVE
CFIndex iTotalBytesRead = 0;
while (true == CFReadStreamHasBytesAvailable(m_ReadStream))
char buffer[1024];
CFIndex bufferLength = 1024;
CFIndex iBytesRead = CFReadStreamRead (
m_ReadStream,
buffer,
bufferLength
// Error ?
if(iBytesRead < 0)
return iBytesRead;
// EOS ?
if(iBytesRead == 0)
return iTotalBytesRead;
iTotalBytesRead += iBytesRead;
if(string != nil)
[string appendString:[NSString stringWithCString:buffer length:(unsigned)iBytesRead]];
3. SEND
CFIndex iBytesSent = CFWriteStreamWrite (
m_WriteStream,
buffer,
bufferLength
Thanks a lot for your help,
Dan